To reproduce: please refer to the attached gif file illustrating the steps how to reproduce the problem with the Demo application. 

Workaround:

        private void radGridView1_CellFormatting(object sender, CellFormattingEventArgs e)
        {
            GridDataCellElement cell = e.CellElement as GridDataCellElement;
            if (cell != null)
            {
                if (cell.ContainsErrors)
                {
                    cell.DrawBorder = true;
                    cell.BorderBoxStyle = BorderBoxStyle.FourBorders;

                    cell.BorderBottomColor = cell.BorderTopColor = cell.BorderRightShadowColor = cell.BorderLeftShadowColor = Color.Transparent;
                    cell.BorderBottomShadowColor = cell.BorderTopShadowColor = cell.BorderRightColor = cell.BorderLeftColor = Color.Red;
                    cell.BorderBottomWidth = cell.BorderTopWidth = cell.BorderRightWidth = cell.BorderLeftWidth = 1;

                    cell.BorderDrawMode = BorderDrawModes.HorizontalOverVertical;
                    cell.ZIndex = 2;
                }
                else
                {
                    cell.ResetValue(LightVisualElement.DrawBorderProperty, ValueResetFlags.Local);
                    cell.ResetValue(LightVisualElement.BorderBoxStyleProperty, ValueResetFlags.Local);

                    cell.ResetValue(LightVisualElement.BorderBottomColorProperty, ValueResetFlags.Local);
                    cell.ResetValue(LightVisualElement.BorderBottomShadowColorProperty, ValueResetFlags.Local);
                    cell.ResetValue(LightVisualElement.BorderBottomWidthProperty, ValueResetFlags.Local);

                    cell.ResetValue(LightVisualElement.BorderTopColorProperty, ValueResetFlags.Local);
                    cell.ResetValue(LightVisualElement.BorderTopShadowColorProperty, ValueResetFlags.Local);
                    cell.ResetValue(LightVisualElement.BorderTopWidthProperty, ValueResetFlags.Local);

                    cell.ResetValue(LightVisualElement.BorderLeftColorProperty, ValueResetFlags.Local);
                    cell.ResetValue(LightVisualElement.BorderLeftShadowColorProperty, ValueResetFlags.Local);
                    cell.ResetValue(LightVisualElement.BorderLeftWidthProperty, ValueResetFlags.Local);

                    cell.ResetValue(LightVisualElement.BorderDrawModeProperty, ValueResetFlags.Local);
                    cell.ResetValue(LightVisualElement.ZIndexProperty, ValueResetFlags.Local);
                }
            }
        }

Use attached to reproduce.
- Use a 125% and 150% monitor for reproducing.
- This should be tested on Windows 10 1803 (Spring Update) as well.

Workaround:
private void RadGridView1_ColumnChooserCreated(object sender, Telerik.WinControls.UI.ColumnChooserCreatedEventArgs e)
{
    e.ColumnChooser = new MyColumnChooser(this.radGridView1.MasterTemplate, radGridView1.GridViewElement);
}

public partial class MyColumnChooser : GridViewColumnChooser
{
    public MyColumnChooser()
    {
        InitializeComponent();
    }
    public MyColumnChooser(GridViewTemplate template, RadGridViewElement rootElement) : base(template, rootElement)
    {
    }
    SizeF oldDpi = new SizeF(1, 1);
    protected override void HandleDpiChanged()
    {

        base.HandleDpiChanged();
        SizeF descale = new SizeF(1f / this.FormElement.DpiScaleFactor.Width, 1f / this.FormElement.DpiScaleFactor.Height);
        this.Scale(descale);
        var dpi = NativeMethods.GetMonitorDpi(Screen.FromRectangle(this.Bounds), NativeMethods.DpiType.Effective);
        if (oldDpi != dpi)
        {
            SizeF sz = new SizeF(dpi.Width / oldDpi.Width, dpi.Height / oldDpi.Height);
       
            this.Scale(dpi);
        }

        oldDpi = dpi;
    }
   
}

To reproduce: please refer to the attached sample gif file. Note that it is important that the child template is bound at design time and the columns are automatically generated. 

Workaround: setup the ViewDefinition programmatically:  

Use attached to reproduce.

Workaround:
private void RadGridView1_ColumnChooserCreated(object sender, Telerik.WinControls.UI.ColumnChooserCreatedEventArgs e)
{
    var columnChooser = e.ColumnChooser as GridViewColumnChooser;
    columnChooser.Shown -= ColumnChooser_Shown;
    columnChooser.Shown += ColumnChooser_Shown;
  
}

private void ColumnChooser_Shown(object sender, EventArgs e)
{
    var columnChooser = sender as GridViewColumnChooser;
    var factor = this.FormElement.DpiScaleFactor;
    columnChooser.Scale(factor);
}

To reproduce: please refer to the attached sample project and gif file.

Workaround: add the column programmatically, not at design time.

How to reproduce: 

public partial class RadForm1 : Telerik.WinControls.UI.RadForm
{
    public RadForm1()
    {
        InitializeComponent();

        this.radGridView1.DataSource = this.GetData();
        this.radGridView1.AutoSizeColumnsMode = Telerik.WinControls.UI.GridViewAutoSizeColumnsMode.Fill;

        GridViewDecimalColumn decimalColumn  = this.radGridView1.Columns[0] as GridViewDecimalColumn;
        decimalColumn.DecimalPlaces = 2;
        decimalColumn.FormatString = "{0:N2}";
        decimalColumn.ExcelExportType = DisplayFormatType.Custom;
        decimalColumn.ExcelExportFormatString = "0.000";
    }

    public object GridViewSpreaExport { get; private set; }

    private object GetData()
    {
        DataTable dt = new DataTable();
        dt.Columns.Add("Id", typeof(double));
        dt.Columns.Add("Name", typeof(string));
        dt.Columns.Add("Bool", typeof(bool));
        dt.Columns.Add("Date", typeof(DateTime));

        for (int i = 0; i < 100; i++)
        {
            dt.Rows.Add(1.10 + i, "Name " + i, i % 2 == 0, DateTime.Now.AddDays(i));
        }

        return dt;
    }

    private void radButton1_Click(object sender, EventArgs e)
    {
        GridViewSpreadStreamExport spreadExporter = new GridViewSpreadStreamExport(this.radGridView1);
        spreadExporter.FileExportMode = FileExportMode.CreateOrOverrideFile;
        SpreadStreamExportRenderer renderer1 = new SpreadStreamExportRenderer();
        spreadExporter.RunExportAsync(@"..\..\exported-stream.xlsx", renderer1);

    }
}

Workaround: Create a custom SpreadStreamExportRenderer

public class CustomSpreadStreamExportRenderer : SpreadStreamExportRenderer
{
    public override void SetCellValue(DataType dataType, object value)
    {
        switch (dataType)
        {
            case DataType.Number:
                this.SetNumberValue(value);
                break;
            case DataType.DateTime:
                this.SetDateTimeValue(value);
                break;
            case DataType.Boolean:
                this.SetBooleanValue(value);
                break;
            case DataType.Other:
                if (this.SetNumberValue(value))
                {
                    break;
                }
                if (this.SetDateTimeValue(value))
                {
                    break;
                }
                if (this.SetBooleanValue(value))
                {
                    break;
                }

                this.SetStringValue(value);
                break;
            case DataType.String:
            default:
                this.SetStringValue(value);
                break;
        }
    }
}

To reproduce: run the attached sample project. Type "res" in the search box very very fast. You will notice that the results with starting with "re" are highlighted. 

Note: it is usually reproducible the first serahc after loading the form. 

To reproduce: set Excel-like filter according to the online documentation: https://docs.telerik.com/devtools/winforms/gridview/filtering/setting-filters-programmatically-(composite-descriptors)

            this.radGridView1.DataSource = this.productsBindingSource;
            this.productsTableAdapter.Fill(this.nwindDataSet.Products);

            this.radGridView1.EnableFiltering = true;
            this.radGridView1.ShowHeaderCellButtons = true;
            
            var filterDescriptor = new FilterDescriptor();
            filterDescriptor.PropertyName = "UnitsInStock";
            filterDescriptor.Value = 101;
            filterDescriptor.Operator = FilterOperator.IsEqualTo;

            var filterDescriptor2 = new FilterDescriptor();
            filterDescriptor2.PropertyName = "UnitsInStock";
            filterDescriptor2.Value = 104;
            filterDescriptor2.Operator = FilterOperator.IsEqualTo;
            var cfd = new CompositeFilterDescriptor();
            cfd.LogicalOperator = FilterLogicalOperator.Or;
            cfd.FilterDescriptors.Add(filterDescriptor);
            cfd.FilterDescriptors.Add(filterDescriptor2);
            cfd.IsFilterEditor = true;
            this.radGridView1.FilterDescriptors.Add(cfd);
            this.radGridView1.MasterTemplate.ExcelFilteredColumns.Add(this.radGridView1.Columns["UnitsInStock"]);

You will notice that the filter popup contains all possible values for this column which is OK, but none of the nodes is checked. It is necessary the visible rows to be checked. 

Workaround: check the nodes programmatically when the popup is shown:

        private void radGridView1_FilterPopupInitialized(object sender, Telerik.WinControls.UI.FilterPopupInitializedEventArgs e)
        {
            RadListFilterPopup popup = e.FilterPopup as RadListFilterPopup;
            if (popup!=null)
            {
                popup.Tag = e.Column.Name;
               popup.PopupOpened-=popup_PopupOpened;
                popup.PopupOpened+=popup_PopupOpened;
            }
        }

        private void popup_PopupOpened(object sender, EventArgs args)
        {
           RadListFilterPopup popup = sender as RadListFilterPopup;

           foreach (GridViewRowInfo row in this.radGridView1.ChildRows)
           {
             RadTreeNode node=   popup.MenuTreeElement.TreeView.FindNodes(row.Cells[popup.Tag+""].Value.ToString()).FirstOrDefault();
             if (node!=null)
             {
                 node.Checked = true;
             }
           }
        }

To reproduce: please refer to the attached sample project and gif file

Workaround:

            GridViewSpreadExport spreadExporter = new GridViewSpreadExport(this.radGridView1);
            spreadExporter.ExportFormat = SpreadExportFormat.Pdf;
            spreadExporter.ExportVisualSettings = true;
            SpreadExportRenderer exportRenderer = new SpreadExportRenderer();
            spreadExporter.RunExport(exportFile, exportRenderer);
            Process.Start(exportFile);

To reproduce: add a grid and a button and use the following code snippet:

[WORKAROUND: call Application.DoEvent at the beginning of the BindGrid method before rebinding]

   public partial class Form1 : Form
    {
        DataTable dtLeg;
        DataTable dtComp;
        DataTable dtClass;
        Int32 intClickCount = 0;
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            try
            {
                BindTables();
            }
            catch(Exception)
            {
                throw;
            }


        }

        private void BindTables()
        {
            try
            {
                dtLeg = new DataTable();
                dtComp = new DataTable();
                dtClass = new DataTable();

                Random rand1 = new Random();
                Random rand2 = new Random();
                Random rand3 = new Random();
                Random rand4 = new Random();

                int cNo = rand1.Next(2000, 10000);
                int dID = rand2.Next(2000, 10000);
                int dDetID = rand3.Next(2000, 10000);
                int depCode = rand4.Next(1000, 8000);
                string cCls = "Leg MIAGCM " + depCode.ToString();


                dtLeg.Columns.Add("Case_Number"); dtLeg.Columns.Add("Departure_Detail_Id"); dtLeg.Columns.Add("Departure_Id"); dtLeg.Columns.Add("Cabin_Class"); dtLeg.Columns.Add("Leg_Segment_type"); dtLeg.Columns.Add("Departure_Detail_Capture_Id");
                dtLeg.Columns.Add("DDC_Compartment_Id"); dtLeg.Columns.Add("Compartment_Structure_Id"); dtLeg.Columns.Add("Compartment_Name"); dtLeg.Columns.Add("Compartment_id"); dtLeg.Columns.Add("DDC_Class_Id"); dtLeg.Columns.Add("Class_Structure_Id");
                dtLeg.Columns.Add("Class_Name"); dtLeg.Columns.Add("Class_id"); dtLeg.Columns.Add("DDC_Subclass_Id"); dtLeg.Columns.Add("Subclass_Structure_Id"); dtLeg.Columns.Add("Subclass_Name"); dtLeg.Columns.Add("Subclass_id");
                dtLeg.Columns.Add("Adjusted_Authorizations"); dtLeg.Columns.Add("Adjusted_Availability"); dtLeg.Columns.Add("Adjusted_Bid_Price"); dtLeg.Columns.Add("Adjusted_Boardings"); dtLeg.Columns.Add("Adjusted_Bookings"); dtLeg.Columns.Add("Adjusted_Load_Factor");
                dtLeg.Columns.Add("Adjusted_Physical_Load_Factor"); dtLeg.Columns.Add("Adjusted_Revenue_Gain"); dtLeg.Columns.Add("Adjusted_SCI"); dtLeg.Columns.Add("Authorized_Capacity"); dtLeg.Columns.Add("Average_Fare_Value"); dtLeg.Columns.Add("Booked_Costs");
                dtLeg.Columns.Add("Booked_Revenue"); dtLeg.Columns.Add("Class_Usage_Ratio"); dtLeg.Columns.Add("Confidence"); dtLeg.Columns.Add("Current_Authorizations"); dtLeg.Columns.Add("Current_Availability"); dtLeg.Columns.Add("Current_Bookings");
                dtLeg.Columns.Add("Current_SCI"); dtLeg.Columns.Add("Go_Shows"); dtLeg.Columns.Add("Group_Bookings"); dtLeg.Columns.Add("Group_No_Show_Percentage"); dtLeg.Columns.Add("Limit_Compartment"); dtLeg.Columns.Add("Max_Constraint_Type");
                dtLeg.Columns.Add("Maximum_Authorizations_Constraint"); dtLeg.Columns.Add("Maximum_Leg_Authorization"); dtLeg.Columns.Add("Min_Constraint_Type"); dtLeg.Columns.Add("Minimum_Authorizations_Constraint"); dtLeg.Columns.Add("No_Show_Percentage"); dtLeg.Columns.Add("No_Shows");
                dtLeg.Columns.Add("Overbooking_Amount"); dtLeg.Columns.Add("Overbooking_Cost"); dtLeg.Columns.Add("Physical_Capacity"); dtLeg.Columns.Add("Projected_Authorized_Load_Factor"); dtLeg.Columns.Add("Projected_Boardings"); dtLeg.Columns.Add("Projected_Bookings");
                dtLeg.Columns.Add("Projected_Physical_Load_Factor"); dtLeg.Columns.Add("Projected_Revenue"); dtLeg.Columns.Add("Recommended_Authorized_Load_Factor"); dtLeg.Columns.Add("Recommended_Authorizations"); dtLeg.Columns.Add("Recommended_Availability"); dtLeg.Columns.Add("Recommended_Bid_Price");
                dtLeg.Columns.Add("Recommended_Boardings"); dtLeg.Columns.Add("Recommended_Bookings"); dtLeg.Columns.Add("Recommended_Physical_Load_Factor"); dtLeg.Columns.Add("Recommended_Revenue"); dtLeg.Columns.Add("Recommended_Revenue_Gain"); dtLeg.Columns.Add("Recommended_SCI");
                dtLeg.Columns.Add("Remaining_Cancellations"); dtLeg.Columns.Add("Original_Demand"); dtLeg.Columns.Add("Remaining_Demand"); dtLeg.Columns.Add("Revenue_Target"); dtLeg.Columns.Add("Standard_Deviation"); dtLeg.Columns.Add("Theoretical_Capacity");
                dtLeg.Columns.Add("Total_Booked_Costs"); dtLeg.Columns.Add("Total_Booked_Revenue"); dtLeg.Columns.Add("Total_Group_Bookings"); dtLeg.Columns.Add("Total_Projected_Demand"); dtLeg.Columns.Add("Total_Waitlist"); dtLeg.Columns.Add("Unit_Target");
                dtLeg.Columns.Add("Upsell_Adjusted_Demand"); dtLeg.Columns.Add("Upsell_Authorizations"); dtLeg.Columns.Add("Upsell_Availability"); dtLeg.Columns.Add("Upsell_Boardings"); dtLeg.Columns.Add("Upsell_Bookings"); dtLeg.Columns.Add("Upsell_Probability");
                dtLeg.Columns.Add("Upsell_Revenue"); dtLeg.Columns.Add("Upsell_Revenue_Gain"); dtLeg.Columns.Add("Upsell_SCI"); dtLeg.Columns.Add("Upsell_Remaining_Demand"); dtLeg.Columns.Add("Usage_Ratio"); dtLeg.Columns.Add("Waitlist");
                dtLeg.Columns.Add("Limit_Class"); dtLeg.Columns.Add("rec_limit"); dtLeg.Columns.Add("curr_limit"); dtLeg.Columns.Add("App_Capacity"); dtLeg.Columns.Add("Rec_Capacity"); dtLeg.Columns.Add("Is_Summary");
                dtLeg.Columns.Add("Current_Resource_Limit1"); dtLeg.Columns.Add("Recommand_Resource_Limit1"); dtLeg.Columns.Add("Upsell_Resource_limit1"); dtLeg.Columns.Add("Adjusted_Resource_limit1"); dtLeg.Columns.Add("Current_Resource_Limit2"); dtLeg.Columns.Add("Recommand_Resource_Limit2");
                dtLeg.Columns.Add("Upsell_Resource_limit2"); dtLeg.Columns.Add("Adjusted_Resource_limit2"); dtLeg.Columns.Add("Include_In_Total_Flag"); dtLeg.Columns.Add("Keep_Curr_Auth"); dtLeg.Columns.Add("Discrete_Recomended_Authorization"); dtLeg.Columns.Add("Discrete_Upsell_Authorization");
                dtLeg.Columns.Add("Nesting_Type"); dtLeg.Columns.Add("BookingPickup_DaysPrior_i"); dtLeg.Columns.Add("BookingPickup_Per_DaysPrior_i"); dtLeg.Columns.Add("BookingPickup_DaysPrior_j"); dtLeg.Columns.Add("BookingPickup_Per_DaysPrior_j"); dtLeg.Columns.Add("BookingPickup_DaysPrior_k");
                dtLeg.Columns.Add("BookingPickup_Per_DaysPrior_k"); dtLeg.Columns.Add("SDL_Booked"); dtLeg.Columns.Add("SDL_Booked_Percentage"); dtLeg.Columns.Add("Travelled_Bookings"); dtLeg.Columns.Add("Travelled_Bookings_Percentage"); dtLeg.Columns.Add("PE_Authorization");
                dtLeg.Columns.Add("PE_Availability"); dtLeg.Columns.Add("PE_Booking"); dtLeg.Columns.Add("PE_Boarding"); dtLeg.Columns.Add("PE_Revenue"); dtLeg.Columns.Add("PE_Revenue_Gain"); dtLeg.Columns.Add("Marginal_Fare");
                dtLeg.Columns.Add("Marginal_Demand"); dtLeg.Columns.Add("Price_Elasticity"); dtLeg.Columns.Add("PE_Group_ID"); dtLeg.Columns.Add("PE_Demand"); dtLeg.Columns.Add("Max_Alloc_Hus"); dtLeg.Columns.Add("PAX_Buffer_Hus");
                dtLeg.Columns.Add("PAX_Buffer_Hus_Type"); dtLeg.Columns.Add("Max_Alloc_Berths"); dtLeg.Columns.Add("PAX_Buffer_Berths"); dtLeg.Columns.Add("PAX_Buffer_Berths_Type"); dtLeg.Columns.Add("IS_Sent"); dtLeg.Columns.Add("StepType");
                dtLeg.Columns.Add("Adjusted_Authorizations_Calc"); dtLeg.Columns.Add("SDL_BP_DP_i"); dtLeg.Columns.Add("SDL_BP_DP_j"); dtLeg.Columns.Add("SDL_BP_DP_k"); dtLeg.Columns.Add("current_revenue"); dtLeg.Columns.Add("revenue_SDL");
                dtLeg.Columns.Add("Diff_Bkd_LY"); dtLeg.Columns.Add("Diff_Bkd_SDL"); dtLeg.Columns.Add("Diff_Revenue"); dtLeg.Columns.Add("Max_Booked");

                DataRow drLeg = dtLeg.NewRow();
                drLeg["Case_Number"] = cNo; drLeg["Departure_Detail_Id"] = dDetID; drLeg["Departure_Id"] = dID; drLeg["Cabin_Class"] = cCls; drLeg["Leg_Segment_type"] = "Leg"; drLeg["Departure_Detail_Capture_Id"] = "43824017"; drLeg["DDC_Compartment_Id"] = System.DBNull.Value;
                drLeg["Compartment_Structure_Id"] = System.DBNull.Value; drLeg["Compartment_Name"] = System.DBNull.Value;


                dtLeg.Rows.Add(drLeg);


                dtComp.Columns.Add("Case_Number"); dtComp.Columns.Add("Departure_Detail_Id"); dtComp.Columns.Add("Departure_Id"); dtComp.Columns.Add("Cabin_Class"); dtComp.Columns.Add("Leg_Segment_type"); dtComp.Columns.Add("Departure_Detail_Capture_Id");
                dtComp.Columns.Add("DDC_Compartment_Id"); dtComp.Columns.Add("Compartment_Structure_Id"); dtComp.Columns.Add("Compartment_Name"); dtComp.Columns.Add("Compartment_id"); dtComp.Columns.Add("DDC_Class_Id"); dtComp.Columns.Add("Class_Structure_Id");
                dtComp.Columns.Add("Class_Name"); dtComp.Columns.Add("Class_id"); dtComp.Columns.Add("DDC_Subclass_Id"); dtComp.Columns.Add("Subclass_Structure_Id"); dtComp.Columns.Add("Subclass_Name"); dtComp.Columns.Add("Subclass_id");
                dtComp.Columns.Add("Adjusted_Authorizations"); dtComp.Columns.Add("Adjusted_Availability"); dtComp.Columns.Add("Adjusted_Bid_Price"); dtComp.Columns.Add("Adjusted_Boardings"); dtComp.Columns.Add("Adjusted_Bookings"); dtComp.Columns.Add("Adjusted_Load_Factor");
                dtComp.Columns.Add("Adjusted_Physical_Load_Factor"); dtComp.Columns.Add("Adjusted_Revenue"); dtComp.Columns.Add("Adjusted_Revenue_Gain"); dtComp.Columns.Add("Adjusted_SCI"); dtComp.Columns.Add("Authorized_Capacity"); dtComp.Columns.Add("Average_Fare_Value"); dtComp.Columns.Add("Booked_Costs");
                dtComp.Columns.Add("Booked_Revenue"); dtComp.Columns.Add("Class_Usage_Ratio"); dtComp.Columns.Add("Confidence"); dtComp.Columns.Add("Current_Authorizations"); dtComp.Columns.Add("Current_Availability"); dtComp.Columns.Add("Current_Bookings");
                dtComp.Columns.Add("Current_SCI"); dtComp.Columns.Add("Go_Shows"); dtComp.Columns.Add("Group_Bookings"); dtComp.Columns.Add("Group_No_Show_Percentage"); dtComp.Columns.Add("Limit_Compartment"); dtComp.Columns.Add("Max_Constraint_Type");
                dtComp.Columns.Add("Maximum_Authorizations_Constraint"); dtComp.Columns.Add("Maximum_Leg_Authorization"); dtComp.Columns.Add("Min_Constraint_Type"); dtComp.Columns.Add("Minimum_Authorizations_Constraint"); dtComp.Columns.Add("No_Show_Percentage"); dtComp.Columns.Add("No_Shows");
                dtComp.Columns.Add("Overbooking_Amount"); dtComp.Columns.Add("Overbooking_Cost"); dtComp.Columns.Add("Physical_Capacity"); dtComp.Columns.Add("Projected_Authorized_Load_Factor"); dtComp.Columns.Add("Projected_Boardings"); dtComp.Columns.Add("Projected_Bookings");
                dtComp.Columns.Add("Projected_Physical_Load_Factor"); dtComp.Columns.Add("Projected_Revenue"); dtComp.Columns.Add("Recommended_Authorized_Load_Factor"); dtComp.Columns.Add("Recommended_Authorizations"); dtComp.Columns.Add("Recommended_Availability"); dtComp.Columns.Add("Recommended_Bid_Price");
                dtComp.Columns.Add("Recommended_Boardings"); dtComp.Columns.Add("Recommended_Bookings"); dtComp.Columns.Add("Recommended_Physical_Load_Factor"); dtComp.Columns.Add("Recommended_Revenue"); dtComp.Columns.Add("Recommended_Revenue_Gain"); dtComp.Columns.Add("Recommended_SCI");
                dtComp.Columns.Add("Remaining_Cancellations"); dtComp.Columns.Add("Original_Demand"); dtComp.Columns.Add("Remaining_Demand"); dtComp.Columns.Add("Revenue_Target"); dtComp.Columns.Add("Standard_Deviation"); dtComp.Columns.Add("Theoretical_Capacity");
                dtComp.Columns.Add("Total_Booked_Costs"); dtComp.Columns.Add("Total_Booked_Revenue"); dtComp.Columns.Add("Total_Group_Bookings"); dtComp.Columns.Add("Total_Projected_Demand"); dtComp.Columns.Add("Total_Waitlist"); dtComp.Columns.Add("Unit_Target");
                dtComp.Columns.Add("Upsell_Adjusted_Demand"); dtComp.Columns.Add("Upsell_Authorizations"); dtComp.Columns.Add("Upsell_Availability"); dtComp.Columns.Add("Upsell_Boardings"); dtComp.Columns.Add("Upsell_Bookings"); dtComp.Columns.Add("Upsell_Probability");
                dtComp.Columns.Add("Upsell_Revenue"); dtComp.Columns.Add("Upsell_Revenue_Gain"); dtComp.Columns.Add("Upsell_SCI"); dtComp.Columns.Add("Upsell_Remaining_Demand"); dtComp.Columns.Add("Usage_Ratio"); dtComp.Columns.Add("Waitlist");
                dtComp.Columns.Add("Limit_Class"); dtComp.Columns.Add("rec_limit"); dtComp.Columns.Add("curr_limit"); dtComp.Columns.Add("App_Capacity"); dtComp.Columns.Add("Rec_Capacity"); dtComp.Columns.Add("Is_Summary");
                dtComp.Columns.Add("Current_Resource_Limit1"); dtComp.Columns.Add("Recommand_Resource_Limit1"); dtComp.Columns.Add("Upsell_Resource_limit1"); dtComp.Columns.Add("Adjusted_Resource_limit1"); dtComp.Columns.Add("Current_Resource_Limit2"); dtComp.Columns.Add("Recommand_Resource_Limit2");
                dtComp.Columns.Add("Upsell_Resource_limit2"); dtComp.Columns.Add("Adjusted_Resource_limit2"); dtComp.Columns.Add("Include_In_Total_Flag"); dtComp.Columns.Add("Keep_Curr_Auth"); dtComp.Columns.Add("Discrete_Recomended_Authorization"); dtComp.Columns.Add("Discrete_Upsell_Authorization");
                dtComp.Columns.Add("Nesting_Type"); dtComp.Columns.Add("BookingPickup_DaysPrior_i"); dtComp.Columns.Add("BookingPickup_Per_DaysPrior_i"); dtComp.Columns.Add("BookingPickup_DaysPrior_j"); dtComp.Columns.Add("BookingPickup_Per_DaysPrior_j"); dtComp.Columns.Add("BookingPickup_DaysPrior_k");
                dtComp.Columns.Add("BookingPickup_Per_DaysPrior_k"); dtComp.Columns.Add("SDL_Booked"); dtComp.Columns.Add("SDL_Booked_Percentage"); dtComp.Columns.Add("Travelled_Bookings"); dtComp.Columns.Add("Travelled_Bookings_Percentage"); dtComp.Columns.Add("PE_Authorization");
                dtComp.Columns.Add("PE_Availability"); dtComp.Columns.Add("PE_Booking"); dtComp.Columns.Add("PE_Boarding"); dtComp.Columns.Add("PE_Revenue"); dtComp.Columns.Add("PE_Revenue_Gain"); dtComp.Columns.Add("Marginal_Fare");
                dtComp.Columns.Add("Marginal_Demand"); dtComp.Columns.Add("Price_Elasticity"); dtComp.Columns.Add("PE_Group_ID"); dtComp.Columns.Add("PE_Demand"); dtComp.Columns.Add("Max_Alloc_Hus"); dtComp.Columns.Add("PAX_Buffer_Hus");
                dtComp.Columns.Add("PAX_Buffer_Hus_Type"); dtComp.Columns.Add("Max_Alloc_Berths"); dtComp.Columns.Add("PAX_Buffer_Berths"); dtComp.Columns.Add("PAX_Buffer_Berths_Type"); dtComp.Columns.Add("IS_Sent"); dtComp.Columns.Add("StepType");
                dtComp.Columns.Add("Adjusted_Authorizations_Calc"); dtComp.Columns.Add("SDL_BP_DP_i"); dtComp.Columns.Add("SDL_BP_DP_j"); dtComp.Columns.Add("SDL_BP_DP_k"); dtComp.Columns.Add("current_revenue"); dtComp.Columns.Add("revenue_SDL");
                dtComp.Columns.Add("Diff_Bkd_LY"); dtComp.Columns.Add("Diff_Bkd_SDL"); dtComp.Columns.Add("Diff_Revenue"); dtComp.Columns.Add("Max_Booked"); dtComp.Columns.Add("COMPARTMENT_STRUCTURE_COMPARTMENT_ORDER");

               

                DataRow drComp = dtComp.NewRow();
                drComp["Case_Number"] = cNo; drComp["Departure_Detail_Id"] = dDetID; drComp["Departure_Id"] = dID; drComp["Cabin_Class"] = cCls; drComp["Leg_Segment_type"] = "Leg"; drComp["Departure_Detail_Capture_Id"] = "43824017"; drComp["DDC_Compartment_Id"] = "60513359";
                drComp["Compartment_Structure_Id"] = 4; drComp["Compartment_Name"] = "J"; drComp["Compartment_id"] = 1; drComp["Adjusted_Authorizations"] = 8; drComp["Adjusted_Availability"] = 7; drComp["Adjusted_Boardings"] = 1; drComp["Adjusted_Bookings"] = 1;
                drComp["Adjusted_Load_Factor"] = 0; drComp["Adjusted_Revenue"] = 349; drComp["Current_Authorizations"] = 8; drComp["Current_Availability"] = 7;

                dtComp.Rows.Add(drComp);

                DataRow drComp1 = dtComp.NewRow();
                drComp1["Case_Number"] = cNo; drComp1["Departure_Detail_Id"] = dDetID; drComp1["Departure_Id"] = dID; drComp1["Cabin_Class"] = cCls; drComp1["Leg_Segment_type"] = "Leg"; drComp1["Departure_Detail_Capture_Id"] = "43824017"; drComp1["DDC_Compartment_Id"] = "60513360";
                drComp1["Compartment_Structure_Id"] = 5; drComp1["Compartment_Name"] = "Y"; drComp1["Compartment_id"] = 2; drComp1["Adjusted_Authorizations"] = 114; drComp1["Adjusted_Availability"] = 97; drComp1["Adjusted_Boardings"] = 39; drComp1["Adjusted_Bookings"] = 39;
                drComp1["Adjusted_Load_Factor"] = 0; drComp1["Adjusted_Revenue"] = 350; drComp1["Current_Authorizations"] = 10; drComp1["Current_Availability"] = 10;

                dtComp.Rows.Add(drComp1);

                dtClass.Columns.Add("Case_Number"); dtClass.Columns.Add("Departure_Detail_Id"); dtClass.Columns.Add("Departure_Id"); dtClass.Columns.Add("Cabin_Class"); dtClass.Columns.Add("Leg_Segment_type"); dtClass.Columns.Add("Departure_Detail_Capture_Id");
                dtClass.Columns.Add("DDC_Compartment_Id"); dtClass.Columns.Add("Compartment_Structure_Id"); dtClass.Columns.Add("Compartment_Name"); dtClass.Columns.Add("Compartment_id"); dtClass.Columns.Add("DDC_Class_Id"); dtClass.Columns.Add("Class_Structure_Id");
                dtClass.Columns.Add("Class_Name"); dtClass.Columns.Add("Class_id"); dtClass.Columns.Add("DDC_Subclass_Id"); dtClass.Columns.Add("Subclass_Structure_Id"); dtClass.Columns.Add("Subclass_Name"); dtClass.Columns.Add("Subclass_id");
                dtClass.Columns.Add("Adjusted_Authorizations"); dtClass.Columns.Add("Adjusted_Availability"); dtClass.Columns.Add("Adjusted_Bid_Price"); dtClass.Columns.Add("Adjusted_Boardings"); dtClass.Columns.Add("Adjusted_Bookings"); dtClass.Columns.Add("Adjusted_Load_Factor");
                dtClass.Columns.Add("Adjusted_Physical_Load_Factor"); dtClass.Columns.Add("Adjusted_Revenue"); dtClass.Columns.Add("Adjusted_Revenue_Gain"); dtClass.Columns.Add("Adjusted_SCI"); dtClass.Columns.Add("Authorized_Capacity"); dtClass.Columns.Add("Average_Fare_Value"); dtClass.Columns.Add("Booked_Costs");
                dtClass.Columns.Add("Booked_Revenue"); dtClass.Columns.Add("Class_Usage_Ratio"); dtClass.Columns.Add("Confidence"); dtClass.Columns.Add("Current_Authorizations"); dtClass.Columns.Add("Current_Availability"); dtClass.Columns.Add("Current_Bookings");
                dtClass.Columns.Add("Current_SCI"); dtClass.Columns.Add("Go_Shows"); dtClass.Columns.Add("Group_Bookings"); dtClass.Columns.Add("Group_No_Show_Percentage"); dtClass.Columns.Add("Limit_Compartment"); dtClass.Columns.Add("Max_Constraint_Type");
                dtClass.Columns.Add("Maximum_Authorizations_Constraint"); dtClass.Columns.Add("Maximum_Leg_Authorization"); dtClass.Columns.Add("Min_Constraint_Type"); dtClass.Columns.Add("Minimum_Authorizations_Constraint"); dtClass.Columns.Add("No_Show_Percentage"); dtClass.Columns.Add("No_Shows");
                dtClass.Columns.Add("Overbooking_Amount"); dtClass.Columns.Add("Overbooking_Cost"); dtClass.Columns.Add("Physical_Capacity"); dtClass.Columns.Add("Projected_Authorized_Load_Factor"); dtClass.Columns.Add("Projected_Boardings"); dtClass.Columns.Add("Projected_Bookings");
                dtClass.Columns.Add("Projected_Physical_Load_Factor"); dtClass.Columns.Add("Projected_Revenue"); dtClass.Columns.Add("Recommended_Authorized_Load_Factor"); dtClass.Columns.Add("Recommended_Authorizations"); dtClass.Columns.Add("Recommended_Availability"); dtClass.Columns.Add("Recommended_Bid_Price");
                dtClass.Columns.Add("Recommended_Boardings"); dtClass.Columns.Add("Recommended_Bookings"); dtClass.Columns.Add("Recommended_Physical_Load_Factor"); dtClass.Columns.Add("Recommended_Revenue"); dtClass.Columns.Add("Recommended_Revenue_Gain"); dtClass.Columns.Add("Recommended_SCI");
                dtClass.Columns.Add("Remaining_Cancellations"); dtClass.Columns.Add("Original_Demand"); dtClass.Columns.Add("Remaining_Demand"); dtClass.Columns.Add("Revenue_Target"); dtClass.Columns.Add("Standard_Deviation"); dtClass.Columns.Add("Theoretical_Capacity");
                dtClass.Columns.Add("Total_Booked_Costs"); dtClass.Columns.Add("Total_Booked_Revenue"); dtClass.Columns.Add("Total_Group_Bookings"); dtClass.Columns.Add("Total_Projected_Demand"); dtClass.Columns.Add("Total_Waitlist"); dtClass.Columns.Add("Unit_Target");
                dtClass.Columns.Add("Upsell_Adjusted_Demand"); dtClass.Columns.Add("Upsell_Authorizations"); dtClass.Columns.Add("Upsell_Availability"); dtClass.Columns.Add("Upsell_Boardings"); dtClass.Columns.Add("Upsell_Bookings"); dtClass.Columns.Add("Upsell_Probability");
                dtClass.Columns.Add("Upsell_Revenue"); dtClass.Columns.Add("Upsell_Revenue_Gain"); dtClass.Columns.Add("Upsell_SCI"); dtClass.Columns.Add("Upsell_Remaining_Demand"); dtClass.Columns.Add("Usage_Ratio"); dtClass.Columns.Add("Waitlist");
                dtClass.Columns.Add("Limit_Class"); dtClass.Columns.Add("rec_limit"); dtClass.Columns.Add("curr_limit"); dtClass.Columns.Add("App_Capacity"); dtClass.Columns.Add("Rec_Capacity"); dtClass.Columns.Add("Is_Summary");
                dtClass.Columns.Add("Current_Resource_Limit1"); dtClass.Columns.Add("Recommand_Resource_Limit1"); dtClass.Columns.Add("Upsell_Resource_limit1"); dtClass.Columns.Add("Adjusted_Resource_limit1"); dtClass.Columns.Add("Current_Resource_Limit2"); dtClass.Columns.Add("Recommand_Resource_Limit2");
                dtClass.Columns.Add("Upsell_Resource_limit2"); dtClass.Columns.Add("Adjusted_Resource_limit2"); dtClass.Columns.Add("Include_In_Total_Flag"); dtClass.Columns.Add("Keep_Curr_Auth"); dtClass.Columns.Add("Discrete_Recomended_Authorization"); dtClass.Columns.Add("Discrete_Upsell_Authorization");
                dtClass.Columns.Add("Nesting_Type"); dtClass.Columns.Add("BookingPickup_DaysPrior_i"); dtClass.Columns.Add("BookingPickup_Per_DaysPrior_i"); dtClass.Columns.Add("BookingPickup_DaysPrior_j"); dtClass.Columns.Add("BookingPickup_Per_DaysPrior_j"); dtClass.Columns.Add("BookingPickup_DaysPrior_k");
                dtClass.Columns.Add("BookingPickup_Per_DaysPrior_k"); dtClass.Columns.Add("SDL_Booked"); dtClass.Columns.Add("SDL_Booked_Percentage"); dtClass.Columns.Add("Travelled_Bookings"); dtClass.Columns.Add("Travelled_Bookings_Percentage"); dtClass.Columns.Add("PE_Authorization");
                dtClass.Columns.Add("PE_Availability"); dtClass.Columns.Add("PE_Booking"); dtClass.Columns.Add("PE_Boarding"); dtClass.Columns.Add("PE_Revenue"); dtClass.Columns.Add("PE_Revenue_Gain"); dtClass.Columns.Add("Marginal_Fare");
                dtClass.Columns.Add("Marginal_Demand"); dtClass.Columns.Add("Price_Elasticity"); dtClass.Columns.Add("PE_Group_ID"); dtClass.Columns.Add("PE_Demand"); dtClass.Columns.Add("Max_Alloc_Hus"); dtClass.Columns.Add("PAX_Buffer_Hus");
                dtClass.Columns.Add("PAX_Buffer_Hus_Type"); dtClass.Columns.Add("Max_Alloc_Berths"); dtClass.Columns.Add("PAX_Buffer_Berths"); dtClass.Columns.Add("PAX_Buffer_Berths_Type"); dtClass.Columns.Add("IS_Sent"); dtClass.Columns.Add("StepType");
                dtClass.Columns.Add("Adjusted_Authorizations_Calc"); dtClass.Columns.Add("SDL_BP_DP_i"); dtClass.Columns.Add("SDL_BP_DP_j"); dtClass.Columns.Add("SDL_BP_DP_k"); dtClass.Columns.Add("current_revenue"); dtClass.Columns.Add("revenue_SDL");
                dtClass.Columns.Add("Diff_Bkd_LY"); dtClass.Columns.Add("Diff_Bkd_SDL"); dtClass.Columns.Add("Diff_Revenue"); dtClass.Columns.Add("Max_Booked"); dtClass.Columns.Add("COMPARTMENT_STRUCTURE_COMPARTMENT_ORDER");


                DataRow drClass = dtClass.NewRow();
                drClass["Case_Number"] = cNo; drClass["Departure_Detail_Id"] = dDetID; drClass["Departure_Id"] = dID; drClass["Cabin_Class"] = cCls; drClass["Leg_Segment_type"] = "Leg"; drClass["Departure_Detail_Capture_Id"] = "43824017"; drClass["DDC_Compartment_Id"] = "60513360";
                drClass["Compartment_Structure_Id"] = 5; drClass["Compartment_Name"] = "Y"; drClass["Compartment_id"] = 2; drClass["DDC_Class_Id"] = "6022025"; drClass["Class_Structure_Id"] = 4;
                drClass["Class_Name"] = "Y"; drClass["Class_id"] = 4; drClass["Adjusted_Authorizations"] = 8; drClass["Adjusted_Availability"] = 7; drClass["Adjusted_Boardings"] = 1; drClass["Adjusted_Bookings"] = 1;
                drClass["Adjusted_Load_Factor"] = 0; drClass["Adjusted_Revenue"] = 349; drClass["Current_Authorizations"] = 8; drClass["Current_Availability"] = 7;

                dtClass.Rows.Add(drClass);

                DataRow drClass1 = dtClass.NewRow();
                drClass1["Case_Number"] = cNo; drClass1["Departure_Detail_Id"] = dDetID; drClass1["Departure_Id"] = dID; drClass1["Cabin_Class"] = cCls; drClass1["Leg_Segment_type"] = "Leg"; drClass1["Departure_Detail_Capture_Id"] = "43824017"; drClass1["DDC_Compartment_Id"] = "60513359";
                drClass1["Compartment_Structure_Id"] = 4; drClass1["Compartment_Name"] = "J"; drClass1["Compartment_id"] = 1; drClass1["DDC_Class_Id"] = "6022020"; drClass1["Class_Structure_Id"] = 1;
                drClass1["Class_Name"] = "J"; drClass1["Class_id"] = 1; drClass1["Adjusted_Authorizations"] = 8; drClass1["Adjusted_Availability"] = 7; drClass1["Adjusted_Boardings"] = 1; drClass1["Adjusted_Bookings"] = 1;
                drClass1["Adjusted_Load_Factor"] = 0; drClass1["Adjusted_Revenue"] = 349; drClass1["Current_Authorizations"] = 8; drClass1["Current_Availability"] = 7;

                dtClass.Rows.Add(drClass1);

                DataRow drClass2 = dtClass.NewRow();
                drClass2["Case_Number"] = cNo; drClass2["Departure_Detail_Id"] = dDetID; drClass2["Departure_Id"] = dID; drClass2["Cabin_Class"] = cCls; drClass2["Leg_Segment_type"] = "Leg"; drClass2["Departure_Detail_Capture_Id"] = "43824017"; drClass2["DDC_Compartment_Id"] = "60513359";
                drClass2["Compartment_Structure_Id"] = 4; drClass2["Compartment_Name"] = "J"; drClass2["Compartment_id"] = 1; drClass2["DDC_Class_Id"] = "6022020"; drClass2["Class_Structure_Id"] = 17;
                drClass2["Class_Name"] = "C"; drClass2["Class_id"] = 17; drClass2["Adjusted_Authorizations"] = 8; drClass2["Adjusted_Availability"] = 7; drClass2["Adjusted_Boardings"] = 1; drClass2["Adjusted_Bookings"] = 1;
                drClass2["Adjusted_Load_Factor"] = 0; drClass2["Adjusted_Revenue"] = 349; drClass2["Current_Authorizations"] = 8; drClass2["Current_Availability"] = 7;

                dtClass.Rows.Add(drClass2);


                BindGrid();
            }
            catch(Exception)
            {
                throw;
            }
        }

        private void BindGrid()
        {
            try
            {

                radGridWorksheet.MasterTemplate.Templates.Clear();
                radGridWorksheet.Relations.Clear();
                radGridWorksheet.DataSource = dtLeg;
                radGridWorksheet.AllowAddNewRow = false;
                radGridWorksheet.AllowDeleteRow = false;
                radGridWorksheet.AllowEditRow = true;
                radGridWorksheet.AutoGenerateColumns = true;
                radGridWorksheet.BestFitColumns();
                radGridWorksheet.GridViewElement.DrawBorder = false;
                radGridWorksheet.GridViewElement.GroupPanelElement.DrawBorder = false;

                GridViewTemplate childDetailCaptureDate = new GridViewTemplate();
                childDetailCaptureDate.Caption = "Leg";
                childDetailCaptureDate.Columns.Clear();
                childDetailCaptureDate.AllowAddNewRow = false;
                childDetailCaptureDate.AllowDeleteRow = false;
                childDetailCaptureDate.AllowEditRow = true;
                childDetailCaptureDate.AutoGenerateColumns = true;
                childDetailCaptureDate.BestFitColumns();
                childDetailCaptureDate.DataSource = dtComp;
                radGridWorksheet.MasterTemplate.Templates.Add(childDetailCaptureDate);
                GridViewRelation relationCaptureDate = new GridViewRelation(radGridWorksheet.MasterTemplate);
                relationCaptureDate.ChildTemplate = childDetailCaptureDate;
                relationCaptureDate.RelationName = "Capture";
                relationCaptureDate.ParentColumnNames.Add("Departure_Detail_Capture_Id");
                relationCaptureDate.ChildColumnNames.Add("Departure_Detail_Capture_Id");
                radGridWorksheet.Relations.Add(relationCaptureDate);

                GridViewTemplate childDetailCaptureDateComp = new GridViewTemplate();
                childDetailCaptureDateComp.Caption = "Comp";
                childDetailCaptureDateComp.Columns.Clear();
                childDetailCaptureDateComp.AllowAddNewRow = false;
                childDetailCaptureDateComp.AllowDeleteRow = false;
                childDetailCaptureDateComp.AllowEditRow = true;
                childDetailCaptureDateComp.AutoGenerateColumns = true;
                childDetailCaptureDateComp.BestFitColumns();
                childDetailCaptureDateComp.DataSource = dtClass;
                childDetailCaptureDate.Templates.Add(childDetailCaptureDateComp);
                GridViewRelation relationCaptureDateCompatment = new GridViewRelation(childDetailCaptureDate);
                relationCaptureDateCompatment.ChildTemplate = childDetailCaptureDateComp;
                relationCaptureDateCompatment.RelationName = "Compartment";
                relationCaptureDateCompatment.ParentColumnNames.Add("DDC_Compartment_Id");
                relationCaptureDateCompatment.ChildColumnNames.Add("DDC_Compartment_Id");
                radGridWorksheet.Relations.Add(relationCaptureDateCompatment); 

                radGridWorksheet.MasterTemplate.ExpandAll();

            }
            catch(Exception e0)
            { 
                MessageBox.Show(String.Format("{0}\n{1}", e0.Message, e0.StackTrace));
                throw;

            }
        }

        private void radButton1_Click(object sender, EventArgs e)
        {
            try
            {
                intClickCount = intClickCount + 1;
                //Thread.Sleep(1000);
                radButton1.Text = "Next Click " + intClickCount;
                BindTables();
            }
            catch(Exception e0)
            { 
                MessageBox.Show(String.Format("{0}\n{1}", e0.Message, e0.StackTrace));
                throw;

            }

        }
    }

To reproduce:
- Create a self reference grid and set the columns width so the horizontal scrollbar is visible. 
- Scroll to the right and filter by the last column,
- Type a single character, the the edited cell is now changed. 

Workaround:
class MyFilterCell : GridFilterCellElement
{
    protected override Type ThemeEffectiveType
    {
        get
        {
            return typeof(GridFilterCellElement);
        }
    }

    public MyFilterCell(GridViewDataColumn column, GridRowElement row) : base(column, row)
    {
        
    }
    public override bool IsCompatible(GridViewColumn data, object context)
    {
        return false;
    }
}

Workaround: handle the SortChanging and FilterChanging events and clear the search criteria from the search row. The stored search string can later be restored in the SortChanged and FilterChanged events

string filter = string.Empty;
private void RadGrid_FilterChanged(object sender, GridViewCollectionChangedEventArgs e)
{
    this.radGrid.MasterView.TableSearchRow.Search(filter);
}

private void RadGrid_SortChanged(object sender, GridViewCollectionChangedEventArgs e)
{
    this.radGrid.MasterView.TableSearchRow.Search(filter);
}

private void RadGrid_SortChanging(object sender, GridViewCollectionChangingEventArgs e)
{
    this.filter = this.radGrid.MasterView.TableSearchRow.SearchCriteria;
    this.radGrid.MasterView.TableSearchRow.Search(null);
}

private void RadGrid_FilterChanging(object sender, GridViewCollectionChangingEventArgs e)
{
    this.filter = this.radGrid.MasterView.TableSearchRow.SearchCriteria;
    this.radGrid.MasterView.TableSearchRow.Search(null);
}

To reproduce:
- Filter a self-referencing grouped grid. 

Workaround:
private void _rgvFreeCodeValues_FilterChanged(object sender, GridViewCollectionChangedEventArgs e)
{
    foreach (var row in RgvFreeCodeValues.Rows)
        row.IsExpanded = false;
}

private void _rgvFreeCodeValues_FilterChanging(object sender, GridViewCollectionChangingEventArgs e)
{
    foreach (var row in RgvFreeCodeValues.Rows)
        row.IsExpanded = true;
}

How to reproduce: 
public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();

        ThemeResolutionService.AllowAnimations = false;
        this.radGridView1.DataSource = this.GetData();
    }

    private DataTable GetData()
    {
        DataTable dt = new DataTable();
        dt.Columns.Add("Id", typeof(int));
        dt.Columns.Add("Name", typeof(string));
        dt.Rows.Add(1, "\u0002x09");
        for (int i = 1; i < 10; i++)
        {
            dt.Rows.Add(i, "name");
        }

        return dt;
    }

    private void radButton1_Click(object sender, EventArgs e)
    {
        GridViewSpreadExport spreadExporter = new GridViewSpreadExport(this.radGridView1);
        spreadExporter.FileExportMode = FileExportMode.CreateOrOverrideFile;
        SpreadExportRenderer exportRenderer = new SpreadExportRenderer();
        spreadExporter.RunExport(@"..\..\exported-file.xlsx", exportRenderer);
    }
}

ArgumentException with clarification similar to  "'\u001f', hexadecimal value 0x1F, is an invalid character." is thrown when trying to export document containing characters which are not supported in XML document - such as some control characters like 0x00, 0x1F, 0x1B, etc. Such characters are described in the XML specification here: https://www.w3.org/TR/xml/#charsets.

Although the escaped strings are not supported (see  https://feedback.telerik.com/Project/184/Feedback/Details/190228 ), the library could prevent the exception and export the document successfully by skipping such characters.

Workaround: remove such characters before the export. Check the following StackOverflow answer for some ideas on code for replacing the characters: http://stackoverflow.com/a/14323524/259206

A similar issue can be also observed in RadTreeView:

Workaround RadGridView: 
private void RadGridView1_CellEditorInitialized(object sender, GridViewCellEventArgs e)
{
    RadTextBoxEditor editor = e.ActiveEditor as RadTextBoxEditor;
    if (editor != null)
    {
        editor.EditorElement.MinSize = new Size(0, 30);
    }
}

Workaround RadTreeView:
 
private void RadTreeView1_EditorInitialized(object sender, TreeNodeEditorInitializedEventArgs e)
{
    TreeViewTextBoxEditor editor = e.Editor as TreeViewTextBoxEditor;
    if (editor != null)
    {
        ((BaseTextBoxEditorElement)editor.EditorElement).TextBoxItem.TextBoxControl.MinimumSize = new Size(0, 24);
    }
}

In 125% the RadTextBox in the Fluent theme keeps shrinking:

Workaround
public RadForm1()
{
    InitializeComponent();

    SizeF dpi = NativeMethods.GetMonitorDpi(Screen.PrimaryScreen, NativeMethods.DpiType.Effective);
    this.radTextBox1.MinimumSize = new Size(0, (int)(24 * dpi.Height));
}

To reproduce: run the attached sample project. 

Type "chef" in the search box and then try to sort some of the columns. Click the header cell several times and as a result the exception will occur.

Workaround:

        public class CustomGrid : RadGridView
        {
            public new object DataSource
            { 
                get
                {
                    return (object)base.DataSource;
                }
                set
                {
                    GridViewSearchRowInfo.Cancel = true;
                    Thread.Sleep(100);
                    base.DataSource = null;
                    this.EnableFiltering = false;
                    base.DataSource = value;
                    this.EnableFiltering = true;
                    base.CurrentRow = null; 
                }
            }
        }

To reproduce:

Please run the sample project and follow the steps from the gif file.

Workaround:

        private void radGridView1_SizeChanged(object sender, EventArgs e)
        {
            this.radGridView1.MasterTemplate.Refresh();
        }

        public class Grid : RadGridView
        {
            public override string ThemeClassName  
            { 
                get 
                { 
                    return typeof(RadGridView).FullName;  
                }
            }

            protected override void OnResize(EventArgs e)
            {
                object value = null;
                if (this.ActiveEditor != null)
                { 
                    value = this.ActiveEditor.Value;  
                }
                base.OnResize(e);
                if (value != null && this.CurrentCell != null)
                {
                    this.CurrentCell.Value = value;
                }
            }
        }

How to reproduce: Create a DPI-aware application and run it on a Windows 10 machine on 125%, the text inside the editors is smaller compared to the text in cells which are not in edit mode.

Workaround: 
private void RadGridView1_CellEditorInitialized(object sender, GridViewCellEventArgs e)
{
    BaseInputEditor editor = e.ActiveEditor as BaseInputEditor;

    if (editor != null)
    {
        RadTextBoxItem item = editor.EditorElement.FindDescendant<RadTextBoxItem>();

        if (item != null)
        {
            item.HostedControl.Font = this.radGridView1.GridViewElement.GetScaledFont(this.radGridView1.GridViewElement.DpiScaleFactor.Height);
        }
    }
} 

To reproduce:
Use the following code
private void RadGridView1_UserAddingRow(object sender, GridViewRowCancelEventArgs e)
{
    radGridView1.MasterView.TableAddNewRow.CancelAddNewRow();
    radGridView1.MasterView.ViewTemplate.DataView.CurrentItem.IsCurrent = false;
}

Place the new row at the bottom. While in edit mode press tab to fill until an exception is thrown.

Workaround:
BaseGridBehavior gridBehavior = radGridView1.GridBehavior as BaseGridBehavior;
gridBehavior.UnregisterBehavior(typeof(GridViewNewRowInfo));
gridBehavior.RegisterBehavior(typeof(GridViewNewRowInfo), new CustomGridRowBehavior());


internal class CustomGridRowBehavior : GridNewRowBehavior
{
    protected override bool ProcessTabKey(KeyEventArgs keys)
    {
        bool newRowIsInEditMode = this.IsInEditMode && this.GridViewElement.CurrentRow is GridViewNewRowInfo;

        if ( newRowIsInEditMode  && this.GridViewElement.Navigator.IsLastEditableColumn(this.GridViewElement.CurrentColumn))              
        {
            this.GridViewElement.Navigator.SelectFirstColumn();

            while (this.GridViewElement.CurrentColumn.ReadOnly && this.GridViewElement.Navigator.SelectNextColumn())
            { }
            return false;
        }
        return base.ProcessTabKey(keys);
    }
}