Steps to reproduce:

1. Add a CompositeFilterDescriptor programmatically as it is demonstrated in the following help article: http://docs.telerik.com/devtools/winforms/gridview/filtering/setting-filters-programmatically-(composite-descriptors)
2. Save the layout.
3. Load the layout.

Use attached project to reproduce.

Workaround:
Seth te PropertyName to a valid column name.

To reproduce use the attached project. 

Workaround:
Private Sub gvData_UserAddedRow(sender As Object, e As Telerik.WinControls.UI.GridViewRowEventArgs) Handles gvData.UserAddedRow
    Dim pi = GetType(GridViewNewRowInfo).GetProperty("MoveToLastRow", Reflection.BindingFlags.Instance Or Reflection.BindingFlags.NonPublic)
    pi.SetValue(Me.gvData.MasterView.TableAddNewRow, True, Nothing)
End Sub

Hello,

we have a RadGridview with a number column and a activated filter for this Grid. 
If we want to filter data by the value "123" the input in the filter textBox is shown as "321.00" (right-to-left).

This is no problem by columns with text values. And at the line for a new data row the input is correct, too.

To reproduce:

DataTable dt = new DataTable();
dt.Columns.Add("Id", typeof(int));
dt.Columns.Add("Name", typeof(string));
dt.Columns.Add("IsActive", typeof(bool));

dt.Rows.Add(1, "Parent1", false);
dt.Rows.Add(2, "Parent2", false);

this.radGridView1.DataSource = dt;
((GridViewCheckBoxColumn)this.radGridView1.MasterTemplate.Columns["IsActive"]).EnableHeaderCheckBox = true;
this.radGridView1.AutoSizeColumnsMode = Telerik.WinControls.UI.GridViewAutoSizeColumnsMode.Fill;

DataTable childDataTable = new DataTable();
childDataTable.Columns.Add("Id", typeof(int));
childDataTable.Columns.Add("Title", typeof(string));
childDataTable.Columns.Add("ParentId", typeof(int));            
childDataTable.Columns.Add("IsValid", typeof(bool));
childDataTable.Rows.Add(1, "Child 1", 1, false);
childDataTable.Rows.Add(2, "Child 1", 1, false);
childDataTable.Rows.Add(3, "Child 2", 2, false);
childDataTable.Rows.Add(4, "Child 2", 2, false);

GridViewTemplate template = new GridViewTemplate();
template.DataSource = childDataTable;            
((GridViewCheckBoxColumn)template.Columns["IsValid"]).EnableHeaderCheckBox = true;
radGridView1.MasterTemplate.Templates.Add(template);
template.AutoSizeColumnsMode = GridViewAutoSizeColumnsMode.Fill;

GridViewRelation relation = new GridViewRelation(radGridView1.MasterTemplate);
relation.ChildTemplate = template;
relation.RelationName = "MasterDeatial";
relation.ParentColumnNames.Add("Id");
relation.ChildColumnNames.Add("ParentId");
radGridView1.Relations.Add(relation);

To reproduce, add menu item in the filtering context menu and upon click, set it as checked. Note that the filtering cell text should also take the custom menu item text or there should be an approach to set it.
Workaround: uncomment the commented code below.

protected override void OnLoad(EventArgs e)
        {
            base.OnLoad(e);

            AddGrid();

            DataTable dt = new DataTable();
            dt.Columns.Add("Id", typeof(int));
            dt.Columns.Add("Name", typeof(string));

            for (int i = 0; i < 5; i++)
            {
                dt.Rows.Add(i, "Item" + i);
            }
            dt.Rows.Add(5, null);
            dt.Rows.Add(6, "");

            radGridView1.ShowHeaderCellButtons = true;
            this.radGridView1.DataSource = dt;
            this.radGridView1.AutoSizeColumnsMode = Telerik.WinControls.UI.GridViewAutoSizeColumnsMode.Fill;
            this.radGridView1.EnableFiltering = true;
            this.radGridView1.EnableCustomFiltering = true;
            //radGridView1.ContextMenuOpening += radGridView1_ContextMenuOpening;
        }

        private void radGridView1_ContextMenuOpening(object sender, Telerik.WinControls.UI.ContextMenuOpeningEventArgs e)
        {
            GridFilterCellElement filterCell = e.ContextMenuProvider as GridFilterCellElement;
            GridViewDataColumn dataCol = (GridViewDataColumn)filterCell.ColumnInfo;
            if (filterCell != null)
            {
                if (filterCell.ColumnInfo.Name == "Name")
                {
                    RadMenuItem isNullMenuItem = new RadMenuItem();
                    isNullMenuItem.Click += customMenuItem_Click;
                    isNullMenuItem.Text = "My IsNull";
                    isNullMenuItem.Tag = filterCell.ColumnInfo.Name;
                    e.ContextMenu.Items.Add(isNullMenuItem);

                    RadMenuItem isNotNullMenuItem = new RadMenuItem();
                    isNotNullMenuItem.Click += customMenuItem_Click;
                    isNotNullMenuItem.Text = "My IsNotNull";
                    isNotNullMenuItem.Tag = filterCell.ColumnInfo.Name;
                    e.ContextMenu.Items.Add(isNotNullMenuItem);

                    bool isCustomFilter = (dataCol.FilterDescriptor != null &&
                        dataCol.FilterDescriptor is CompositeFilterDescriptor &&
                        dataCol.FilterDescriptor.Expression.Contains("NULL"));

                    foreach (RadMenuItem item in e.ContextMenu.Items)
                    {
                        if (item.Text == "Is null" || item.Text == "Is not null")
                        {
                            item.Visibility = Telerik.WinControls.ElementVisibility.Collapsed;
                        }
                        //if (isCustomFilter)
                        //{
                        //    item.IsChecked = false;
                        //}
                    }
                    //if (isCustomFilter)
                    //{
                    //    if (((CompositeFilterDescriptor)dataCol.FilterDescriptor).LogicalOperator == FilterLogicalOperator.And)
                    //    {
                    //        isNotNullMenuItem.IsChecked = true;
                    //    }
                    //    else
                    //    {
                    //        isNullMenuItem.IsChecked = true;
                    //    }
                    //}
                }
            }
        }

        private void customMenuItem_Click(object sender, EventArgs e)
        {
            RadMenuItem clickedItem = (RadMenuItem)sender;
            string columnName = clickedItem.Tag.ToString();
            radGridView1.Columns[columnName].FilterDescriptor = null;

            FilterOperator filterOperator = clickedItem.Text.Contains("Not") ? FilterOperator.IsNotEqualTo : FilterOperator.IsEqualTo;
            FilterLogicalOperator logicalOperator = clickedItem.Text.Contains("Not") ? FilterLogicalOperator.And : FilterLogicalOperator.Or;

            CompositeFilterDescriptor compositeFilter = new CompositeFilterDescriptor();
            compositeFilter.FilterDescriptors.Add(new FilterDescriptor(columnName, filterOperator, ""));
            compositeFilter.FilterDescriptors.Add(new FilterDescriptor(columnName, filterOperator, null));
            compositeFilter.LogicalOperator = logicalOperator;
            compositeFilter.IsFilterEditor = true;
            this.radGridView1.FilterDescriptors.Add(compositeFilter);

            clickedItem.IsChecked = true;
        }

To reproduce: run the attached sample project. You will notice the result illustrated in the provided screenshot. Although the grid is RTL, the print preview dialog show it in LTR.

Workaround:

public class CustomGridPrintStyle : GridPrintStyle
{
    protected override BaseGridPrintRenderer InitializePrintRenderer(RadGridView grid)
    {
        if (this.PrintRenderer != null)
        {
            this.PrintRenderer.PrintCellPaint -= renderer_PrintCellPaint;
            this.PrintRenderer.PrintCellFormatting -= renderer_PrintCellFormatting;
            this.PrintRenderer.ChildViewPrinting -= renderer_ChildViewPrinting;
        }

        BaseGridPrintRenderer renderer = null;

        if (grid.ViewDefinition.GetType() == typeof(ColumnGroupsViewDefinition))
        {
            if (!(renderer is ColumnGroupsViewDefinitionPrintRenderer))
            {
                renderer = new CustomColumnGroupsViewDefinitionPrintRenderer(grid);
            }
        }
        else if (grid.ViewDefinition.GetType() == typeof(HtmlViewDefinition))
        {
            if (!(renderer is HtmlViewDefinitionPrintRenderer))
            {
                renderer = new HtmlViewDefinitionPrintRenderer(grid);
            }
        }
        else
        {
            if (!(renderer is TableViewDefinitionPrintRenderer))
            {
                renderer = new TableViewDefinitionPrintRenderer(grid);
            }
        }

        renderer.ChildViewPrinting += renderer_ChildViewPrinting;
        renderer.PrintCellFormatting += renderer_PrintCellFormatting;
        renderer.PrintCellPaint += renderer_PrintCellPaint;

        return renderer; 
    }

    private void renderer_PrintCellPaint(object sender, PrintCellPaintEventArgs e)
    {
        this.OnPrintCellPaint(sender, e);
    }

    private void renderer_PrintCellFormatting(object sender, PrintCellFormattingEventArgs e)
    {
        this.OnPrintCellFormatting(sender, e);
    }

    private void renderer_ChildViewPrinting(object sender, ChildViewPrintingEventArgs e)
    {
        this.OnChildViewPrinting(sender, e);
    }
}

public class CustomColumnGroupsViewDefinitionPrintRenderer : ColumnGroupsViewDefinitionPrintRenderer
{
    public CustomColumnGroupsViewDefinitionPrintRenderer(RadGridView grid) : base(grid)
    {
    }

    protected override void PrintRow(GridViewRowInfo row, ColumnGroupRowLayout rowLayout, GridPrintSettings settings, int currentX, int currentY, Graphics graphics)
    { 
        float scrollableColumnsOffset = 0f;
        float rightPinnedColumnsOffset = 0f;

        foreach (GridViewColumn col in rowLayout.RenderColumns)
        {
            if (col is GridViewRowHeaderColumn || col is GridViewIndentColumn)
            {
                continue;
            }

            float height = rowLayout.GetRowHeight(row);
            RectangleF cellBounds = rowLayout.GetCorrectedColumnBounds(row, col, this.GridView.RightToLeft == RightToLeft.Yes,
                new RectangleF(0f, 0f, rowLayout.DesiredSize.Width, height));

            if (cellBounds == RectangleF.Empty)
            {
                continue;
            }

            if (col.PinPosition == PinnedColumnPosition.Left)
            {
                if (scrollableColumnsOffset < cellBounds.Right + rowLayout.Owner.CellSpacing)
                {
                    scrollableColumnsOffset = cellBounds.Right + rowLayout.Owner.CellSpacing;
                    rightPinnedColumnsOffset = scrollableColumnsOffset;
                }
            }
            else if (col.PinPosition == PinnedColumnPosition.None)
            {
                if (rightPinnedColumnsOffset < scrollableColumnsOffset + cellBounds.Right + rowLayout.Owner.CellSpacing)
                {
                    rightPinnedColumnsOffset = scrollableColumnsOffset + cellBounds.Right + rowLayout.Owner.CellSpacing;
                }

                cellBounds.X += scrollableColumnsOffset;
            }
            else
            {
                cellBounds.X += rightPinnedColumnsOffset;
            }

            cellBounds.Offset(currentX, currentY);

            GridViewCellInfo cell;
            CellPrintElement printCell;

            if (row is GridViewTableHeaderRowInfo)
            {
                cell = this.GridView.MasterView.TableHeaderRow.Cells[col.Name];

                printCell = this.CreateHeaderCellPrintElement(col);
                if (printCell.Font != settings.HeaderCellFont)
                {
                    if (settings.HeaderCellFont != null)
                    {
                        printCell.Font = settings.HeaderCellFont;
                    }
                    else
                    {
                        settings.HeaderCellFont = printCell.Font;
                    }
                }
            }
            else if (row is GridViewSummaryRowInfo)
            {
                GridViewSummaryRowInfo rowInfo = row as GridViewSummaryRowInfo;
                cell = rowInfo.Cells[col.Name];

                if (cell == null)
                {
                    continue;
                }

                printCell = this.CreateSummaryCellPrintElement(cell);
                if (printCell.Font != settings.SummaryCellFont)
                {
                    if (settings.SummaryCellFont != null)
                    {
                        printCell.Font = settings.SummaryCellFont;
                    }
                    else
                    {
                        settings.SummaryCellFont = printCell.Font;
                    }
                }
            }
            else
            {
                cell = row.Cells[col.Name];

                if (cell == null)
                {
                    continue;
                }

                if (col is GridViewImageColumn)
                {
                    printCell = this.CreateImageCellPrintElement(cell);
                }
                else
                {
                    printCell = this.CreateDataCellPrintElement(cell);
                    if (printCell.Font != settings.CellFont)
                    {
                        if (settings.CellFont != null)
                        {
                            printCell.Font = settings.CellFont;
                        }
                        else
                        {
                            settings.CellFont = printCell.Font;
                        }
                    }
                }
            }

            printCell.TextPadding = this.GridView.PrintStyle.CellPadding;
            printCell.RightToLeft = this.GridView.RightToLeft == RightToLeft.Yes;

            Rectangle rect = new Rectangle((int)cellBounds.X, (int)cellBounds.Y, (int)cellBounds.Width, (int)cellBounds.Height);

            PrintCellFormattingEventArgs formattEventArgs = new PrintCellFormattingEventArgs(row, col, printCell);
            this.OnPrintCellFormatting(formattEventArgs);

            formattEventArgs.PrintCell.Paint(graphics, rect);
           
            PrintCellPaintEventArgs paintEventArgs = new PrintCellPaintEventArgs(graphics, row, col, rect);
            this.OnPrintCellPaint(paintEventArgs);               
        }
    }
}

private void radButton1_Click(object sender, EventArgs e)
{ 
    CustomGridPrintStyle style = new CustomGridPrintStyle();
    
    this.radGridView1.PrintStyle = style;
    RadPrintDocument printDoc = new RadPrintDocument();
    printDoc.Landscape = true;
    printDoc.RightHeader = "Right Header";
    printDoc.HeaderHeight = 100;
    printDoc.AssociatedObject = this.radGridView1;
    
    RadPrintPreviewDialog dialog = new RadPrintPreviewDialog(printDoc);
    
    dialog.Size = new System.Drawing.Size(Screen.PrimaryScreen.Bounds.Width - 200, Screen.PrimaryScreen.Bounds.Height - 200);
    dialog.SetZoom(0.80);
    dialog.ShowDialog();
}

There should be a way for users to determine if a row passes a certain filter criteria without that affecting any data operations.

The GridViewCheckBoxColumn.EditMode property controls when the value of the editor will be submitted to the cell. By default, the value is OnValidate and the value will be submitted only when the current cell changes, the grid looses focus or the active editor is closed by pressing Enter. If you set the EditMode property to OnValueChange it will submit the value immediately after the editor value changes. Please refer to the attached gif files illustrating the difference between the two modes.

To reproduce: if you set the GridViewCheckBoxColumn.EnableHeaderCheckBox property to true, the cell value is always submitted immediately after toggle/untoggle the checkbox without considering that EditMode.OnValidate is used.

How to reproduce: 
 public partial class Form1 : Form
 {
     public Form1()
     {
         InitializeComponent();
         GridViewDecimalColumn decimalColumn = new GridViewDecimalColumn();
         decimalColumn.Name = "DecimalColumn";
         decimalColumn.HeaderText = "DecimalColumn";
         this.radGridView1.MasterTemplate.Columns.Add(decimalColumn);

         GridViewTextBoxColumn textBoxColumn = new GridViewTextBoxColumn();
         textBoxColumn.Name = "TextBoxColumn";
         textBoxColumn.HeaderText = "TextBoxColumn";
         this.radGridView1.MasterTemplate.Columns.Add(textBoxColumn);

         GridViewDateTimeColumn dateTimeColumn = new GridViewDateTimeColumn();
         dateTimeColumn.Name = "DateTimeColumn";
         dateTimeColumn.HeaderText = "DateTimeColumn";
         this.radGridView1.MasterTemplate.Columns.Add(dateTimeColumn);
     }
 }

Workaround: this.radGridView1.MasterView.TableAddNewRow.MinHeight = 30;

When the EnableHeaderCheckBox property is set to true, whenever the checkbox is clicked in the new row, a new row is actually added to the grid before any other modifications are made. This can be replicated in the attached sample project. Run it and click the checkbox in the new row several times. Multiple rows are added.  

Workaround: cancel the RadGridView.UserAddingRow until all the required fields are filled.

To reproduce: 

public Form1()
{
    InitializeComponent();
     
    DataTable dt = new DataTable();
    dt.Columns.Add("Id");
    dt.Columns.Add("Name");
    for (int i = 0; i < 1; i++)
    {
        dt.Rows.Add(i, "Item");
    }
    this.radGridView1.DataSource = dt;
    this.radGridView1.SelectionMode = GridViewSelectionMode.FullRowSelect;
    this.radGridView1.ClipboardCopyMode = Telerik.WinControls.UI.GridViewClipboardCopyMode.EnableAlwaysIncludeHeaderText;
    this.radGridView1.MultiSelect = true; 
}

private void button1_Click(object sender, EventArgs e)
{
    this.radGridView1.SelectAll();
    this.radGridView1.Copy();
}

If you click the button, you will notice that only one cell is copied. However, if you add 2 and more rows, the whole grid content will be copied to the clipboard.

Workaround: use the BeginRowCopy/EndRowCopy methods.

private void button1_Click(object sender, EventArgs e)
{
    this.radGridView1.SelectAll();
    this.radGridView1.MasterTemplate.BeginRowCopy();
    this.radGridView1.Copy();
    this.radGridView1.MasterTemplate.EndRowCopy();
}

To reproduce:
- Add several columns including combo-box columns to a grid. 
- Add one row and upon a button click, change the data source of the combo column.

Workaround: 

Seth the following field to null prior changing the data source: 

    GetType(GridViewComboBoxColumn).GetField("nullBoundItem", Reflection.BindingFlags.Instance Or Reflection.BindingFlags.NonPublic).SetValue(combo, Nothing)
    combo.DataSource = dt

To reproduce: add a RadGridView and a RadButton on the form. Use the following code snippet:

public RadForm1()
{
    InitializeComponent();
    this.radGridView1.Columns.Add("Col1");
    this.radGridView1.Columns.Add("Col2");
    for (int i = 0; i < 5; i++)
    {
        this.radGridView1.Rows.Add(i, "Item" + i);
    }
    this.radGridView1.AutoSizeColumnsMode = Telerik.WinControls.UI.GridViewAutoSizeColumnsMode.Fill;
    this.radGridView1.RowValidating += radGridView1_RowValidating;
    this.radGridView1.UserAddingRow += radGridView1_UserAddingRow;
}

private void radGridView1_UserAddingRow(object sender, Telerik.WinControls.UI.GridViewRowCancelEventArgs e)
{
    e.Cancel = true;
}

private void radGridView1_RowValidating(object sender, Telerik.WinControls.UI.RowValidatingEventArgs e)
{
    if (e.Row.IsModified && e.Row is GridViewDataRowInfo)
    { 
        e.Cancel = true;
    }
}

private void radButton1_Click(object sender, EventArgs e)
{ 
    RadMessageBox.Show("Clicked");
}

1. Select a data cell and activate the editor. Enter some new value and click the button. The Click event is fired.
2. Select the new row and activate the editor. Enter some value and click the button. The Click event is NOT fired.

Workaround: use the CellValidating event instead.

To reproduce:

Sub New()
     
    InitializeComponent()

    Dim dt1 As New DataTable
    dt1.Columns.Add("Id", GetType(Integer))
    dt1.Columns.Add("Name", GetType(String))
    For index = 1 To 20
        dt1.Rows.Add(index, "Parent" & index)
    Next
    Me.RadGridView1.MasterTemplate.DataSource = dt1
    Me.RadGridView1.AutoSizeColumnsMode = GridViewAutoSizeColumnsMode.Fill

    Dim dt2 As New DataTable
    dt2.Columns.Add("Id", GetType(Integer))
    dt2.Columns.Add("Name", GetType(String))
    dt2.Columns.Add("ParentId", GetType(Integer))

    Dim dt3 As New DataTable
    dt3.Columns.Add("Id", GetType(Integer))
    dt3.Columns.Add("Name", GetType(String))
    dt3.Columns.Add("ParentId", GetType(Integer))
    For index = 1 To 20
        If index Mod 2 = 0 Then
            dt2.Rows.Add(index, "Child1." & index, index)
            If index Mod 4 = 0 Then
                dt3.Rows.Add(index, "Child2." & index, index)
            End If
        ElseIf index Mod 3 = 0 Then
            dt3.Rows.Add(index, "Child2." & index, index)
        Else
            dt3.Rows.Add(index, "Child2." & index, index)
        End If

    Next

    Dim template As New GridViewTemplate()
    template.DataSource = dt2
    template.AutoSizeColumnsMode = GridViewAutoSizeColumnsMode.Fill
    RadGridView1.MasterTemplate.Templates.Add(template)

    Dim relation As New GridViewRelation(RadGridView1.MasterTemplate)
    relation.ChildTemplate = template
    relation.RelationName = "FirstChild"
    relation.ParentColumnNames.Add("Id")
    relation.ChildColumnNames.Add("ParentId")
    RadGridView1.Relations.Add(relation)

    Dim template2 As New GridViewTemplate()
    template2.DataSource = dt3
    template2.AutoSizeColumnsMode = GridViewAutoSizeColumnsMode.Fill
    RadGridView1.MasterTemplate.Templates.Add(template2)

    Dim relation2 As New GridViewRelation(RadGridView1.MasterTemplate)
    relation2.ChildTemplate = template2
    relation2.RelationName = "SecondChild"
    relation2.ParentColumnNames.Add("Id")
    relation2.ChildColumnNames.Add("ParentId")
    RadGridView1.Relations.Add(relation2)

    AddHandler Me.RadGridView1.ChildViewExpanding, AddressOf ChildViewExpanding
End Sub

Private Sub RadGridView1_ViewCellFormatting(sender As Object, e As Telerik.WinControls.UI.CellFormattingEventArgs) _
Handles RadGridView1.ViewCellFormatting
    Dim cell As GridDetailViewCellElement = TryCast(e.CellElement, GridDetailViewCellElement)
    Dim expanderCell As GridGroupExpanderCellElement = TryCast(e.CellElement, GridGroupExpanderCellElement)
    If expanderCell IsNot Nothing AndAlso TypeOf e.CellElement.RowElement Is GridDataRowElement Then
        Dim hierarchyRow As GridViewHierarchyRowInfo = DirectCast(expanderCell.RowInfo, GridViewHierarchyRowInfo)
        If Not IsExpandable(hierarchyRow) Then
            expanderCell.Expander.Visibility = Telerik.WinControls.ElementVisibility.Hidden
        Else
            expanderCell.Expander.Visibility = Telerik.WinControls.ElementVisibility.Visible
        End If
    ElseIf cell IsNot Nothing Then
        Dim hierarchyRow As GridViewHierarchyRowInfo = DirectCast(DirectCast(cell.RowInfo, GridViewDetailsRowInfo).Owner,  _
        GridViewHierarchyRowInfo)
        For i As Integer = 0 To cell.PageViewElement.Items.Count - 1
            Dim item As RadPageViewItem = cell.PageViewElement.Items(i)
            Dim viewInfo As GridViewInfo = hierarchyRow.Views(i)
            item.Text = "Child Template " & i
            If viewInfo.ChildRows.Count = 0 Then
                If i = 0 AndAlso i < cell.PageViewElement.Items.Count - 1 Then
                    cell.PageViewElement.Items(i + 1).IsSelected = True
                End If
                item.Visibility = Telerik.WinControls.ElementVisibility.Hidden
            Else
                item.Visibility = Telerik.WinControls.ElementVisibility.Visible
            End If
        Next
    End If
End Sub

Private Function IsExpandable(hierarchyRow As GridViewHierarchyRowInfo) As Boolean
    For Each view As GridViewInfo In hierarchyRow.Views
        If view.ChildRows.Count > 0 Then
            Return True
        End If
    Next
    Return False
End Function

Workaround:

AddHandler Me.RadGridView1.ChildViewExpanding, AddressOf RadGridView1_ChildViewExpanding 
AddHandler Me.RadGridView1.MouseDown, AddressOf RadGridView_MouseDown

Private Sub RadGridView1_ChildViewExpanding(sender As Object, e As ChildViewExpandingEventArgs)
    If lastClicked IsNot Nothing AndAlso e.ParentRow.Equals(lastClicked) Then
        e.Cancel = False
    Else
        e.Cancel = True
    End If

End Sub

Dim lastClicked As GridViewRowInfo

Private Sub RadGridView_MouseDown(sender As Object, e As MouseEventArgs)
    Dim expander As GridExpanderItem = TryCast(Me.RadGridView1.ElementTree.GetElementAtPoint(e.Location), GridExpanderItem)
    If expander IsNot Nothing Then
        lastClicked = DirectCast(expander.Parent, GridGroupExpanderCellElement).RowInfo 
    End If 
End Sub

To reproduce:
- Add GridViewTextBoxColumn and set the MaxLength property.
- Paste in data row while the is not in edit mode.

Workaround:
private void RadGridView1_Pasting(object sender, Telerik.WinControls.UI.GridViewClipboardEventArgs e)
{
    if (radGridView1.CurrentColumn.Name == "column1")
    {
        GridViewTextBoxColumn col = new GridViewTextBoxColumn();
        var lenght = col.MaxLength;
        if (Clipboard.ContainsData(DataFormats.Text))
        {
            e.Cancel = true;
            string data = Clipboard.GetData(DataFormats.Text).ToString();
            radGridView1.CurrentCell.Value = data.Substring(0, lenght);
        }
    }
}

 

Steps to reproduce:

1. Add a CompositeFilterDescriptor programmatically as it is demonstrated in the following help article: http://docs.telerik.com/devtools/winforms/gridview/filtering/setting-filters-programmatically-(composite-descriptors)
2. Save the layout.
3. Load the layout.

Workaround: specify the PropertyName property for the CompositeFilterDescriptor.

To reproduce:

Sub New()
     
    InitializeComponent()

    Dim dt As New DataTable
    dt.Columns.Add("Id", GetType(Integer))
    dt.Columns.Add("Name", GetType(String))
    dt.Columns.Add("Description", GetType(String))

    For index = 1 To 5
        dt.Rows.Add(index, "Item" & index, "Description" & index)
    Next
    Me.RadGridView1.DataSource = dt
    Me.RadGridView1.AutoSizeColumnsMode = Telerik.WinControls.UI.GridViewAutoSizeColumnsMode.Fill
    
    AddHandler Me.RadGridView1.UserAddingRow, AddressOf UserAddingRow

End Sub

Private Sub UserAddingRow(sender As Object, e As Telerik.WinControls.UI.GridViewRowCancelEventArgs)
    Me.RadGridView1.MasterView.TableAddNewRow.ErrorText = ""
    If String.IsNullOrEmpty(e.Rows(0).Cells(0).Value) Then
        e.Cancel = True
        Me.RadGridView1.MasterView.TableAddNewRow.ErrorText = "Empty value is not allowed!"
    End If
End Sub

1. Click the new row and enter a value in the last cell. 
2. Click outside the new row, e.g. click on a data row. The UserAddingRow event is canceled and the new row remains current. 
3. Click a data row again without any modification on the new row. The new row is not current anymore. 
4. However, you perform step 1and 2 but instead of clicking a data row, the user clicks a header cell, the new row is not current from the first time. It is necessary to forbid the user to exit the new row until the validation passes or the new row is canceled by pressing Enter.

Workaround:  use the CellValidating/RowValidating event for validating.

Consider the case where there are many child views and you want to export only the ones that actually contain data. 
Currently, you can either export only one view or all. 

One should be able to pass all the views in the ChildViewExporting event.

Workaround: create a custom GridDetailViewCellElement
Public Class Form1
    Sub New()

        InitializeComponent()

        AddHandler dgvPatients.CreateCell, AddressOf dgvPatients_CreateCell

    End Sub

    Private Sub dgvPatients_CreateCell(sender As Object, e As GridViewCreateCellEventArgs)
        If e.CellType = GetType(GridDetailViewCellElement) Then
            e.CellElement = New MyGridDetailViewCellElement(e.Column, e.Row)
        End If
    End Sub

End Class

Public Class MyGridDetailViewCellElement
    Inherits GridDetailViewCellElement

    Sub New(column As GridViewColumn, rowElement As GridRowElement)
        MyBase.New(column, rowElement)
    End Sub

    Public Overrides Sub UpdateTabItemsVisibility()
        If Me.DetailsRow Is Nothing Then
            Return
        End If

        MyBase.UpdateTabItemsVisibility()
    End Sub

End Class