Steps at design time:
1.Add a RadGridView to the from and change its Dock property to Fill.
2.Change its AutoSizeColumnsMode property to Fill.
3.Chage the Form.Size property to Width = 527 and Height = 346.

Use the following code:
public Form1()
{
    InitializeComponent();

    DataTable dt = new DataTable("Items");

    dt.Columns.Add("Id", typeof(int));
    dt.Columns.Add("Description", typeof(string));
    dt.Columns.Add("Price", typeof(decimal));
    dt.Columns.Add("Supplier", typeof(string));

    for (int i = 0; i < 10; i++)
    {
        dt.Rows.Add(i, "Description" + i, i * 0.25, "Supplier" + i);
    }

    radGridView1.DataSource = dt;
}

Workaround: set the AutoSizeColumnsMode property to Fill in the Form.Load event:
private void Form1_Load(object sender, EventArgs e)
{
    radGridView1.AutoSizeColumnsMode = GridViewAutoSizeColumnsMode.Fill;
}

DECLINED: this happens only when the double click is outside the bounds of the scroll button which is the expected behavior.

To reproduce: When the user clicks too fast on the quite thin area between the grid's scroll-bar arrow button and the row, it fires the CurrentRowChanging event.

Workaround:
private bool cancelChanging = false;

private void radGridView1_CurrentRowChanging(object sender, CurrentRowChangingEventArgs e)
{
if (cancelChanging)
{
e.Cancel = true;
cancelChanging = false;
}
}

private void radGridView1_MouseDoubleClick(object sender, MouseEventArgs e)
{
cancelChanging = false;

RadElement element = this.radGridView1.Behavior.GetHoveredRadElement();

while (element != null)
{
if (element.GetType() == typeof(RadScrollBarElement))
{
cancelChanging = true;
break;
}
element = element.Parent;
}
}

To reproduce:
Add a RadGridView and use the following code. When you expand the first row, the vertical scrollbar is not correct. Scrolling down changes its size. However, if you expand the last row, it takes few seconds to open.

Second scenario:
In addition of the following code, if you change the TableElement.PageViewMode to PageViewMode.ExplorerBar, expanding the first row takes few seconds to load the hierarchical data as well.

public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();

        List<Item> items = new List<Item>();
        List<SubItem> subItems = new List<SubItem>();

        for (int i = 1; i <= 3; i++)
        {
            Item item = new Item(i, "Item" + i);
            
            for (int j = 1000; j <= 2010; j++)
            {
                subItems.Add(new SubItem(j, "SubItem" + j, i));
            }

            items.Add(item);
        }

        this.radGridView1.DataSource = items;
        this.radGridView1.AutoSizeColumnsMode = GridViewAutoSizeColumnsMode.Fill;

        GridViewTemplate template = new GridViewTemplate();
        template.ReadOnly = true;
        template.AutoSizeColumnsMode = GridViewAutoSizeColumnsMode.Fill;

        GridViewRelation relation = new GridViewRelation(this.radGridView1.MasterTemplate, template);
        relation.ParentColumnNames.Add("Id");
        relation.ChildColumnNames.Add("ItemId");
        this.radGridView1.MasterTemplate.Templates.Add(template);
        this.radGridView1.Relations.Add(relation);
        template.DataSource = subItems;
    }
}

public class Item
{
    public int Id { get; set; }

    public string Title { get; set; }

    public Item(int id, string title)
    {
        this.Id = id;
        this.Title = title;
    }
}

public class SubItem
{
    public int Id { get; set; }

    public int ItemId { get; set; }

    public string Name { get; set; }
    
    public SubItem(int id, string name, int itemId)
    {
        this.Id = id;
        this.ItemId = itemId;
        this.Name = name;
    }
}

To reproduce:
1.Add a GridViewCheckBoxColumn and populate the grid with data:
radGridView1.DataSource = Enumerable.Range(1, 100).Select(i => new { Check = i % 2 == 0});
2.Add a RadButton and on its Click event clear the filters:
private void radButton1_Click(object sender, EventArgs e)
{
    radGridView1.MasterTemplate.FilterDescriptors.Clear();
}
3.Run the application and change the filter to show only checked items. Then click the button. The check box in the filtering row for GridViewCheckBoxColumn was not updated properly.

Workaround:
this.radGridView1.BeginUpdate();
radGridView1.MasterTemplate.FilterDescriptors.Clear();
this.radGridView1.EndUpdate();

To reproduce:
1.Use the Self-Referencing Hierarchy help article to fill the grid with data.
2.Subscribe to the ChildViewExpanding event and use the following code snippet:
private void radGridView1_ChildViewExpanding(object sender, ChildViewExpandingEventArgs e)
{
    if (e.ParentRow.ChildRows != null && e.ParentRow.ChildRows.Count > 0)
    {
        e.ParentRow.ChildRows[0].Delete();
    }
}

This issue appears when one clears the relations collection of RadGridView, it appears sporadically and in rare cases

To reproduce:


Create a form and add a timer with interval of 1 second and in tick handler do the following:


void t_Tick(object sender, EventArgs e)
{
    if (this.Controls.Count > 0)
    {
        Control oldGrid = this.Controls[0];
        this.Controls.RemoveAt(0);
        oldGrid.Dispose();




        GC.Collect(3, GCCollectionMode.Forced);
    }




    RadGridView grid = new RadGridView();
    grid.Dock = DockStyle.Fill;
    this.Controls.Add(grid);
}


You will see that the memory consumption will grow.


Workaround:


Use the following custom RadGridView


public class MyRadGridView : RadGridView
{
    protected override RadGridViewElement CreateGridViewElement()
    {
        return new MyElement();
    }
}


public class MyElement : RadGridViewElement
{
    protected override PagingPanelElement CreatePagingPanelElement()
    {
        return new MyPagingPanel();
    }


    protected override Type ThemeEffectiveType
    {
        get
        {
            return typeof(RadGridViewElement);
        }
    }
}


public class MyPagingPanel : PagingPanelElement
{
    protected override void CreateButtonsStripElementChildElements()
    {
        base.CreateButtonsStripElementChildElements();


        this.ButtonsStripElement.Children.Add(this.ButtonsStripElement.Grip);
        this.ButtonsStripElement.Children.Add(this.ButtonsStripElement.OverflowButton);


        this.ButtonsStripElement.Grip.Visibility = this.ButtonsStripElement.OverflowButton.Visibility = ElementVisibility.Collapsed;
    }


    protected override void CreateTextBoxStripElementChildElements()
    {
        base.CreateTextBoxStripElementChildElements();


        this.TextBoxStripElement.Children.Add(this.TextBoxStripElement.Grip);
        this.TextBoxStripElement.Children.Add(this.TextBoxStripElement.OverflowButton);


        this.TextBoxStripElement.Grip.Visibility = this.TextBoxStripElement.OverflowButton.Visibility = ElementVisibility.Collapsed;
    }
}

To reproduce:
- Add RadGridView to a blank project and bind it to a blank binding source.
- Add GridViewMultiComboBoxColumn to the grid and bind it to another binding source.
- In the CellEditorInitialized set the autocomplete mode to Suggest.
- When you start the application you will notice that the first items is selected but not displayed and to display it you should select other value first and you will be able to select the first one.

Workaround:
Set the selected item of the editor to null in the CellEditorInitialized event.

Add the ability to filter by empty values (not null values) just like in excel.

To reproduce:
- Add some rows to a grid view and set the ClipboardCopyMode to EnableAlwaysIncludeHeaderText.
- Copy entire row and paste it in excel. You will notice that the columns are pasted right, but the cells values are merged.
- Also when multiple rows are copied the issue does not occur.

The RadGridView designer allows you to add columns and make changes while debugging the application. When you click the Ok button it tells you that your changes cannot be applied and everything is lost. I've done this several times by accident and didn't realize I was debugging until my changes were lost. Maybe disallow making changes to the columns while debugging?

The binding source filtering should be synchronized with the grid one in case other controls are using the same binding source.

To reproduce:
- Set the AutoSizeRows and PrintGrouping properties to true.
- Add a group descriptor and then call the PrintPreview method of the grid.

Workaround:
- Use the following classes to create custom print style:
public class MyGridPrintRenderer : TableViewDefinitionPrintRenderer
{
    private RadGridView gridView;

    public MyGridPrintRenderer(RadGridView grid) : base(grid)
    {
        gridView = grid;
    }

    protected override int GetDataRowHeight(GridViewRowInfo row, TableViewRowLayoutBase rowLayout)
    {
        IVirtualizedElementProvider<GridViewRowInfo> rowElementProvider = this.gridView.TableElement.RowScroller.ElementProvider;
        GridRowElement visualRow = rowElementProvider.GetElement(row, null) as GridRowElement;
        if (visualRow is GridGroupHeaderRowElement)
        {
            return rowLayout.GetRowHeight(row);
        }
        return base.GetDataRowHeight(row, rowLayout);
    }
}

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

        MyGridPrintRenderer renderer = new MyGridPrintRenderer(grid);

        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);
    }
}

To reproduce:

Add a RadGridView and three GridViewComboBoxColumns with repetitive values:

for (int i = 0; i < 3; i++)
{
    List<int> datasource = new List<int>();
    for (int j = 0; j < 12; j++)
    {
        datasource.Add(j);
    }
    this.Grid.Columns.Add(new GridViewComboBoxColumn()
        {
            DataSource = datasource
        });
}

for (int i = 0; i < 10; i++)
{
    for (int j = 0; j < 5; j++)
    {
        this.Grid.Rows.Add(i, i, i);
    }
}

Start the project and sort second and last column by the same value and make sure that you have vertical scrollbar.

Select a cell in the second column change its value and press the tab key(or click on another cell in the same row). You will see that the scrollbar will go to the bottom of the grid.

Workaround:

Use the following class:

public class ActionExecuteHelper
    {
        #region Singleton

        private static ActionExecuteHelper instance;
        private static readonly object syncRoot = new object();

        public static ActionExecuteHelper Instance
        {
            get
            {
                if (instance == null)
                {
                    lock (syncRoot)
                    {
                        if (instance == null)
                        {
                            instance = new ActionExecuteHelper();
                        }
                    }
                }
                return instance;
            }
        }

        #endregion

        private readonly Timer timer;

        public ActionExecuteHelper()
        {
            this.timer = new Timer();
        }

        public void ExecuteDelayedAction(Action action, int delayInMilliseconds)
        {
            EventHandler timerTick = null;

            timerTick = delegate
            {
                this.timer.Stop();
                this.timer.Tick -= timerTick;
                action.Invoke();
            };

            this.timer.Tick += timerTick;
            this.timer.Interval = delayInMilliseconds;
            this.timer.Start();
        }
    }


And use it with the following code

private int savedValue;
private void Grid_CellEndEdit(object sender, GridViewCellEventArgs e)
{
    this.Grid.TableElement.VScrollBar.ValueChanged += ValueChangedDelegate;
}

private void ValueChangedDelegate(object sender, EventArgs e)
{
    this.Grid.TableElement.VScrollBar.ValueChanged -= ValueChangedDelegate;
    ActionExecuteHelper.Instance.ExecuteDelayedAction(new Action(this.SetScrollbarValue), 5);
}

private void SetScrollbarValue()
{
    this.Grid.TableElement.VScrollBar.Value = savedValue;
}

private void Grid_ValueChanging(object sender, ValueChangingEventArgs e)
{
    this.savedValue = this.Grid.TableElement.VScrollBar.Value;
}

This way the value of the scrollbar will be saved and restored.

Description:
When you pin data rows from the child template to PinnedRowPosition.Top, it does not affect the row. However, when you pin the certain row to PinnedRowPosition.Bottom, the behavior is correct. The same issue is detected for the header rows from the child template.

Workaround: use the CellValidating event 

To reproduce:

Sub New()
    InitializeComponent()

    Dim dt As New DataTable()

    For index = 1 To 13
        If index = 4 Then
            dt.Columns.Add("Col" & index, Type.GetType("System.Int32"))
        Else
            dt.Columns.Add("Col" & index)
        End If

    Next

    Dim rand As New Random
    For index = 1 To 9000
        Dim newRow As DataRow = dt.NewRow()
        For Each col As DataColumn In dt.Columns
            If col.ColumnName = "Col4" Then
                newRow(col.ColumnName) = rand.Next(2, 1000).ToString()
            Else
                newRow(col.ColumnName) = "Data" & index.ToString() & "." & dt.Columns.IndexOf(col).ToString()
            End If


        Next

        dt.Rows.Add(newRow)
    Next

    Me.RadGridView1.DataSource = dt

    Me.RadGridView1.AutoSizeColumnsMode = Telerik.WinControls.UI.GridViewAutoSizeColumnsMode.Fill

    Me.RadGridView1.Columns.RemoveAt(3)

    Dim list As New List(Of CustomerMaster)
    For index = 1 To 1000
        list.Add(New CustomerMaster((index + 1), "Name" & (1000 - index + 1).ToString()))
    Next


    Dim CustomerMaster_IDColumn As GridViewComboBoxColumn = New GridViewComboBoxColumn
        With CustomerMaster_IDColumn
        .Name = "CustomerMaster_ID"
        .HeaderText = "Customer Master"
        .DataSource = list
        .ValueMember = "Id"
        .DisplayMember = "Name"
        .FieldName = "Col4"
        .Width = 200
        .DisplayMemberSort = True
        .DropDownStyle = Telerik.WinControls.RadDropDownStyle.DropDownList
    End With

    Me.RadGridView1.Columns.Insert(3, CustomerMaster_IDColumn)

End Sub

Public Class CustomerMaster
    Private _id As String
    Private _name As String

    Public Sub New(id As String, name As String)
        Me._id = id
        Me._name = name
    End Sub

    Public Property Id() As String
        Get
            Return _id
        End Get
        Set(ByVal value As String)
            _id = value
        End Set
    End Property

    Public Property Name() As String
        Get
            Return _name
        End Get
        Set(ByVal value As String)
            _name = value
        End Set
    End Property

End Class

To reproduce:

Add a RadGridView. Create a DataTable with 3 columns with data type - Decimal. To the last column set the following expression - "column1 + column2". Add some rows with some values. Turn on excel like filtering - http://www.telerik.com/help/winforms/gridview-filtering-excel-like-filtering.html. Subscribe to the CellValueChanged event and add the following code:

if (this.radGridView1.CurrentRow.DataBoundItem != null)
            {
                ((DataRowView)this.radGridView1.CurrentRow.DataBoundItem).Row.EndEdit(); // force row subtotal update
            }


Start the application and filter the last column by some of the available values. Change a value in one of the first two cells. You will notice that the last cell's value is not updated although it is updated in the data table.  This behavior does not occur when the grid is not filtered.

To reproduce: use the code from our demo application for Custom Filtering. Instead of Customers table, bind the grid to Orders or another table with 1000+ rows.

Resolution: You can surround the row operation in Begin/EndUpdate(false) and remove the InvalidateRow method. The Custom Filtering example in our demo Application is updated for better performance or you can use the following code snippet: 

For example:


        private void radGridView1_CustomFiltering(object sender, Telerik.WinControls.UI.GridViewCustomFilteringEventArgs e)
        {

            if (string.IsNullOrEmpty(this.radTextBox1.Text))
            {
                this.radGridView1.BeginUpdate();
                e.Visible = true;
                for (int i = 0; i < this.radGridView1.ColumnCount; i++)
                {
                    e.Row.Cells[i].Style.Reset();
                  
                }
                //e.Row.InvalidateRow();
                this.radGridView1.EndUpdate(false);
                return;
            }

            this.radGridView1.BeginUpdate();
            e.Visible = false;
            for (int i = 0; i < this.radGridView1.ColumnCount; i++)
            {
                string text = e.Row.Cells[i].Value.ToString();
                if (text.IndexOf(this.radTextBox1.Text, 0, StringComparison.InvariantCultureIgnoreCase) >= 0)
                {
                    e.Visible = true;
                    e.Row.Cells[i].Style.CustomizeFill = true;
                    e.Row.Cells[i].Style.DrawFill = true;
                    e.Row.Cells[i].Style.BackColor = Color.FromArgb(201, 252, 254);
                }
                else
                {
                    e.Row.Cells[i].Style.Reset();
                    
                }
            }
            //e.Row.InvalidateRow();
            this.radGridView1.EndUpdate(false);
        }