To reproduce:

Open the examples and navigate to GridView -> RightToLeft and toggle on RightToLeft. You will see that the GridGroupHeaderRowElements will have its text LeftToRight.

Workaround:

Use ViewCellFormatting:

private void Grid_ViewCellFormatting15(object sender, CellFormattingEventArgs e)
{
    if (e.CellElement.RowElement is GridGroupHeaderRowElement && e.CellElement.RowElement.Children.Any() && e.CellElement.RowElement.Children.Last() is GridGroupContentCellElement)
    {
        (e.CellElement.RowElement.Children.Last() as GridGroupContentCellElement).TextAlignment = System.Drawing.ContentAlignment.MiddleRight;
    }
}

To reproduce:
- Set  EnterKeyMode to EnterMovesToNextRow.
- Enter an invalid value in the first cell and press enter two times.
- Enter valid value and press enter again.
- You will notice that the current row is moved appropriately.

To reproduce:
Private Sub Form1_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
    Me.ProductsTableAdapter.Fill(Me.NwindDataSet.Products)
    Dim menu As New ContextMenu()
    For index = 1 To 4
        menu.MenuItems.Add("item" & index)
    Next
    Me.ContextMenu = menu
End Sub

Workaround:

Const WM_CONTEXTMENU As Integer = &H7B

Public Class Grid
Inherits RadGridView
    Protected Overrides Sub WndProc(ByRef m As Message)
        If m.Msg = WM_CONTEXTMENU Then
            Return
        End If
        MyBase.WndProc(m)
    End Sub

    Public Overrides Property ThemeClassName As String
        Get
            Return GetType(RadGridView).FullName
        End Get
        Set(value As String)
            MyBase.ThemeClassName = value
        End Set
    End Property
End Class

To reproduce:
-Add GridViewMaskBoxColumn to a grid.
-Set the Mask type to Regex and set any mask you want.
-When you leave the cell NullRefernceException is thrown.

To reproduce: 
1. Add a RadGridView and bind it to Northwind.Products table.
2. Use the following code:

 Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
     Me.ProductsTableAdapter.Fill(Me.NwindDataSet.Products)
     For Each col As GridViewColumn In Me.RadGridView1.Columns
         If Not col.HeaderText = "SupplierID" AndAlso Not col.HeaderText = "ProductID" Then
             col.ReadOnly = True
         End If
     Next
     Me.RadGridView1.AddNewRowPosition = SystemRowPosition.Bottom
 End Sub

 Private Sub RadGridView1_CellValidating(sender As Object, e As CellValidatingEventArgs) Handles RadGridView1.CellValidating
     If e.Value Is Nothing Then
         If MessageBox.Show("Incorrect", "error", MessageBoxButtons.OKCancel) = Windows.Forms.DialogResult.OK Then
             e.Cancel = True
         End If
     End If
 End Sub

3. Run the project and go to the new row ,cell "SupplierID".
4. Clear the value and press Tab key. As a result the message box for error indication is shown twice.

Workaround:
'register the custom row  behavior
Dim gridBehavior As BaseGridBehavior = TryCast(RadGridView1.GridBehavior, BaseGridBehavior)
gridBehavior.UnregisterBehavior(GetType(GridViewNewRowInfo))
gridBehavior.RegisterBehavior(GetType(GridViewNewRowInfo), New MyNewRowBehavior())

Me.RadGridView1.GridViewElement.Navigator = New MyGridNavigator()


Public Class MyNewRowBehavior
Inherits GridNewRowBehavior
    Protected Overrides Function ProcessTabKey(keys As KeyEventArgs) As Boolean
        If Me.GridControl.AddNewRowPosition = SystemRowPosition.Bottom AndAlso _
        Me.GridControl.IsInEditMode AndAlso Me.GridViewElement.Navigator.IsLastColumn(GridViewElement.CurrentColumn) Then
            Me.GridControl.Tag = "SuspendValidation"
        End If
        Return MyBase.ProcessTabKey(keys)
    End Function
End Class

Public Class MyGridNavigator
Inherits BaseGridNavigator
    Public Overrides Function SelectFirstColumn() As Boolean
        If Me.GridViewElement.GridControl.Tag = "SuspendValidation" Then
            Me.GridViewElement.GridControl.Tag = Nothing
            Return False
        End If
        Return MyBase.SelectFirstColumn()
    End Function
End Class

To reproduce:
1. Add a RadGridView and a RadButton.
2. Enable paging.
3. Use the code snippet below: 
private void Form1_Load(object sender, EventArgs e)
{
    this.ordersTableAdapter.Fill(this.nwindDataSet.Orders);

    bs.DataSource = this.ordersBindingSource;
    this.radGridView1.DataSource = bs;
}
BindingSource bs = new BindingSource();

private void radButton1_Click(object sender, EventArgs e)
{
    bs.Filter ="ShipName LIKE '%z%'";
}
4. Navigate to page 80 and click the button.
5. You have only 4 pages available , but you are still positioned on page 80.

Workaround:
private void radButton1_Click(object sender, EventArgs e)
{
    bs.Filter ="ShipName LIKE '%z%'";
    if (this.radGridView1.MasterTemplate.PageIndex>this.radGridView1.MasterTemplate.TotalPages)
    {
        this.radGridView1.MasterTemplate.MoveToFirstPage();
    }
}

Currently one cannot set the column chooser items properties permanently since they are recreated every time the chooser is shown or item is added/removed.

Resolution: 
You can subscribe to the ColumnChooserItemElementCreating event and edit the column chooser items.

To reproduce:

Setup RadGridView as follows:

this.Grid.MasterTemplate.EnablePaging = true;
this.Grid.Columns.Add("");
this.Grid.Columns.Add("");
this.Grid.Columns.Add("");
this.Grid.Columns.Add("");

On a button click add rows:

private void Button_Clic9k(object sender, EventArgs e)
{
    for (int i = 0; i < 120; i++)
    {
        this.Grid.Rows.AddNew();
    }
}

You will see a vertical scrollbar when it is not needed.

Workaround:

Wrap the loop in a Begin/EndUpdate calls:

private void Button_Clic9k(object sender, EventArgs e)
{
    this.Grid.BeginUpdate();
    for (int i = 0; i < 120; i++)
    {
        this.Grid.Rows.AddNew();
    }

    this.Grid.EndUpdate();
}

When RadGridView is in right to left mode and the data is grouped, the layout of the items that represent the group field names is incorrect - the close button overlays the text.

WORKAROUND:

        public Form83()
        {
            new RadControlSpyForm().Show();
            InitializeComponent();

            this.radGridView1.GroupByChanged += radGridView1_GroupByChanged;
        }

        void radGridView1_GroupByChanged(object sender, Telerik.WinControls.UI.GridViewCollectionChangedEventArgs e)
        {
            foreach (GroupFieldElement fieldElement in this.radGridView1.GridViewElement.GroupPanelElement.GetDescendants(
                delegate(RadElement element) { return element is GroupFieldElement; }, Telerik.WinControls.TreeTraversalMode.BreadthFirst))
            {
                fieldElement.TextAlignment = ContentAlignment.MiddleRight;
            }
        }

To reproduce:

DataTable dt = new DataTable();

public Form1()
{
    InitializeComponent();

    this.radGridView1.EnableFiltering = true;
    this.radGridView1.ShowHeaderCellButtons = true;

    this.radGridView1.Relations.AddSelfReference(this.radGridView1.MasterTemplate, "ID", "ParentID");
    
    dt.Columns.Add("ID", typeof(int));
    dt.Columns.Add("Title", typeof(string));
    dt.Columns.Add("ParentID", typeof(int));

    for (int i = 1; i <= 5; i++)
    {
        dt.Rows.Add(i, "Parent." + i, 0);
    }

    Random rand = new Random();
    for (int i = 6; i < 20; i++)
    {
        dt.Rows.Add(i, "Child." + i, rand.Next(1, 6));  
    }

    for (int i = 20; i < 40; i++)
    {
        dt.Rows.Add(i, "SubChild." + i, rand.Next(6, 20));  
    }

    this.radGridView1.DataSource = dt;
    this.radGridView1.AutoSizeColumnsMode = GridViewAutoSizeColumnsMode.Fill;
}

To reproduce:
1.Add a RadGridView and add twelve columns at design time.
2.Enable filtering and use the following code:

public Form1()
{
    InitializeComponent();
    radGridView1.MasterTemplate.MultiSelect = true;
}
private void Form1_Load(object sender, EventArgs e)
{
    foreach (var column in radGridView1.Columns)
    {
        column.Width = 100;
    }
}
3.When you run the application, click over the filtering cell for the 3rd column. Type in some text and click the filter button. As a result the horizontal scroll bar is positioned at right most.

Workaround:
radGridView1.MouseDown += radGridView1_MouseDown;
radGridView1.TableElement.HScrollBar.ValueChanged += HScrollBar_ValueChanged;

int scrollBarValue = 0;
bool shouldResetValue = false;

private void radGridView1_MouseDown(object sender, MouseEventArgs e)
{
    RadElement clickecElement = this.radGridView1.ElementTree.GetElementAtPoint(e.Location);
    GridFilterRowElement filterRowElement = clickecElement.FindAncestor<GridFilterRowElement>();
    GridNewRowElement newRowElement = clickecElement.FindAncestor<GridNewRowElement>();
    if (clickecElement is GridFilterRowElement || clickecElement is GridNewRowElement ||
        filterRowElement != null || newRowElement != null)
    {
        shouldResetValue = true;
    }
    else
    {
        shouldResetValue = false;
    }
    scrollBarValue = this.radGridView1.TableElement.HScrollBar.Value;
}

private void HScrollBar_ValueChanged(object sender, EventArgs e)
{
    if (shouldResetValue)
    {
        this.radGridView1.TableElement.HScrollBar.Value = scrollBarValue;
    }
}

If one sets AutoSizeRows to true and AllowSearchRow to true the layout of RadGridView throws an exception.

Resolution: 
Please use the following code snippet to replace RadGridViewDragDropService: 
this.radGridView1.GridViewElement.RegisterService(new CustomDragDropService(this.radGridView1.GridViewElement));  

To reproduce:
Use the code snippet below:

static DataSet ds;

public form1()
{
    InitializeComponent(); 
    GridviewStyling(radGridView1);
    ds = PrepareDataset();
    BuildGrid();

    //Set_Hierarchy();
    for (int i = 0; i < radGridView1.Templates.Count; i++)
        GridviewTemplateStyling(radGridView1.Templates[i]);

    this.radGridView1.TableElement.PageViewMode = PageViewMode.ExplorerBar;
    this.radGridView1.ViewCellFormatting += radGridView1_ViewCellFormatting;
}

       void radGridView1_ViewCellFormatting(object sender, CellFormattingEventArgs e)
{
    GridDetailViewCellElement detailCell = e.CellElement as GridDetailViewCellElement;
    if (detailCell != null)
    {
        GridViewHierarchyRowInfo hierarchyRow = (GridViewHierarchyRowInfo)((GridViewDetailsRowInfo)detailCell.RowInfo).Owner;
        detailCell.PageViewElement.Header.Visibility = Telerik.WinControls.ElementVisibility.Collapsed;
        RadPageViewElement el = detailCell.PageViewElement as RadPageViewExplorerBarElement;
        if (el != null)
        {
            for (int i = 0; i < el.Items.Count; i++) // detailCell.PageViewElement.Items.Count
            {
                RadPageViewItem item = detailCell.PageViewElement.Items[i];
                GridViewInfo viewInfo = hierarchyRow.Views[i];
                item.MaxSize = new Size(0, 1);
                item.Visibility = Telerik.WinControls.ElementVisibility.Hidden;
                if (viewInfo.ChildRows.Count != 0)
                {
                    item.Visibility = Telerik.WinControls.ElementVisibility.Collapsed;
                }
            }
        }
    }
}

private DataSet PrepareDataset()
{
    Random r = new Random();
    DataSet ds = new DataSet("DS");

    //snir
    DataTable dtFirst = new DataTable("Snir");
    dtFirst.Columns.Add("pId", typeof(int));
    dtFirst.Columns.Add("Col1", typeof(int));
    dtFirst.Columns.Add("Col", typeof(string));
    dtFirst.Columns.Add("Col3", typeof(int));
    dtFirst.Columns.Add("Col4", typeof(string));
    for (int i = 0; i < 5; i++)
        dtFirst.Rows.Add(1, i, "snirsnirsnir" + r.Next(0, 100).ToString(),
            r.Next(0, 35), "snir" + r.Next(0, 100).ToString());

    // jenny
    DataTable dtSecond = new DataTable("Jenny");
    dtSecond.Columns.Add("pId", typeof(int));
    dtSecond.Columns.Add("Col1", typeof(int));
    dtSecond.Columns.Add("Col2", typeof(string));
    dtSecond.Columns.Add("Col3", typeof(int));
    dtSecond.Columns.Add("Col4", typeof(string));
    dtSecond.Columns.Add("Col5", typeof(string));
    dtSecond.Columns.Add("Col6", typeof(string));
    for (int i = 0; i < 5; i++)
        dtSecond.Rows.Add(2, i, "CnC" + r.Next(0, 100).ToString(),
            r.Next(0, 35), "jenny" + r.Next(0, 100).ToString(), "col5", "col6");

    //index
    DataTable table1 = new DataTable("Index");
    table1.Columns.Add("TableId", typeof(int));
    table1.Columns.Add("TableName", typeof(string));
    table1.Columns.Add("UpdateType", typeof(int));
    table1.Rows.Add(1, dtFirst.TableName, r.Next(0, 3));
    table1.Rows.Add(2, dtSecond.TableName, r.Next(0, 3));

    ds.Tables.AddRange(new DataTable[] { table1, dtFirst, dtSecond });

    return ds;
}

private void BuildGrid()
{
    // bind the master template
    this.radGridView1.DataSource = ds;
    this.radGridView1.DataMember = "Index";

    //templates
    GridViewTemplate template1 = new GridViewTemplate();
    template1.DataSource = ds.Tables[1];
    template1.Columns[0].IsVisible = false;
    template1.EnableHierarchyFiltering = false;
    template1.ShowGroupedColumns = false;

    radGridView1.Templates.Add(template1);

    GridViewTemplate template2 = new GridViewTemplate();
    template2.DataSource = ds.Tables[2]; // 1:snir   // 2:jenny
    radGridView1.Templates.Add(template2);
    template1.AllowDragToGroup = false;

    //relations
    GridViewRelation relation1 = new GridViewRelation(radGridView1.MasterTemplate);//, template2);
    relation1.RelationName = "myRelation1";
    relation1.ChildTemplate = radGridView1.Templates[0];
    relation1.ChildColumnNames.AddRange(new string[] { "pId" });
    relation1.ParentColumnNames.Add("TableId");
    radGridView1.Relations.Add(relation1);

    GridViewRelation relation2 = new GridViewRelation(radGridView1.MasterTemplate);//, template2);
    relation2.RelationName = "myRelation2";
    relation2.ChildTemplate = radGridView1.Templates[1];
    relation2.ChildColumnNames.AddRange(new string[] { "pId" });
    relation2.ParentColumnNames.Add("TableId");
    radGridView1.Relations.Add(relation2);
}

private void GridviewStyling(RadGridView rgv)
{
    //radGridView1 styling
    rgv.AllowAddNewRow = false;
    rgv.EnableGrouping = false;
    rgv.AllowDragToGroup = false;

    rgv.AllowDrop = false;
    rgv.AllowEditRow = false;
    rgv.AllowDrop = false;
    rgv.AllowRowResize = false;

    rgv.AllowColumnResize = false;
    rgv.AutoExpandGroups = true;
    rgv.AutoSizeColumnsMode = Telerik.WinControls.UI.GridViewAutoSizeColumnsMode.Fill;
    rgv.EnableCustomGrouping = false;

    rgv.ShowColumnHeaders = true;
    rgv.ShowRowHeaderColumn = false;
    rgv.ShowGroupPanel = false;
}

private void GridviewTemplateStyling(GridViewTemplate gvt)
{
    //template styling
    gvt.AllowAddNewRow = false;
    gvt.Columns[0].IsVisible = false;
    gvt.ShowChildViewCaptions = false;

    gvt.AllowDragToGroup = false;
    gvt.AllowRowResize = false;
    gvt.AllowColumnResize = false;
    gvt.AutoExpandGroups = true;

    gvt.AutoSizeColumnsMode = Telerik.WinControls.UI.GridViewAutoSizeColumnsMode.Fill;
    gvt.ShowRowHeaderColumn = false;
    gvt.ShowColumnHeaders = true;
}

private string GetEnumString(int n)
{
    switch (n)
    {
        case (int)TableUpdateModeEnum.INSERT:
            return "INSERT";
        case (int)TableUpdateModeEnum.UPDATE:
            return "UPDATE";
        case (int)TableUpdateModeEnum.UPDATE_OR_INSERT:
            return "UPDATE/DELETE";
        case (int)TableUpdateModeEnum.DELETE_OR_INSERT:
            return "INSERT/DELETE";
        default:
            return "";
    }
}

public enum TableUpdateModeEnum
{
    [Description("Snir")]
    INSERT = 0,
    [Description("Liraz")]
    UPDATE_OR_INSERT = 1,
    [Description("Jenny")]
    UPDATE = 2,
    [Description("Tsuria")]
    DELETE_OR_INSERT = 3
};        

Scenario:
1.Expand a master row.
2.Start dragging columns from the child template.
3.When your are dragging over the thick border , the exception occur.

To reproduce:
- Add the following column to a blank grid and new row or edit the existing one:
GridViewMaskBoxColumn maskBoxColumn = new GridViewMaskBoxColumn();
maskBoxColumn.Name = "Dates";
maskBoxColumn.HeaderText = "Dates";
maskBoxColumn.MaskType = MaskType.FreeFormDateTime;
maskBoxColumn.DataType = typeof(System.DateTime);
radGridView1.MasterTemplate.Columns.Add(maskBoxColumn);
this.radGridView1.Rows.Add(DateTime.Now.AddDays(5));

To reproduce:

Add a RadGridView with some data and enable the paging functionality. Also set the AutoSize property to true:

grid.EnablePaging = true;
grid.AutoSize = true;

Start the application and you will see that when you try to edit the textbox with the number of the page you will not be able to.

Workaround:

Set the AutoSize property to false and use MinimumSize instead:

grid.AutoSize = false;
grid.MinimumSize = new Size(600, 500);

 RadGridView, TextBoxColumn - add support for autocomplete.

To reproduce:

public Form1()
{
    InitializeComponent();
    radGridView1.ToolTipTextNeeded += radGridView1_ToolTipTextNeeded;
}

private void radGridView1_ToolTipTextNeeded(object sender, ToolTipTextNeededEventArgs e)
{
    GridDataCellElement cell = sender as GridDataCellElement;
    if (cell != null)
    {
        e.ToolTipText = cell.Value.ToString();
        toolTipText = e.ToolTipText;
        e.ToolTip.OwnerDraw = true;
        e.ToolTip.Draw += ToolTip_Draw;
        e.ToolTip.Popup += ToolTip_Popup;
    }
}

private void ToolTip_Popup(object sender, PopupEventArgs e)
{
    e.ToolTipSize = TextRenderer.MeasureText(toolTipText + "   ", newFont);
}

Font newFont = new Font("Arial", 15f, FontStyle.Bold);
string toolTipText = string.Empty;

private void ToolTip_Draw(object sender, DrawToolTipEventArgs e)
{
    e.Graphics.FillRectangle(SystemBrushes.Control, e.Bounds);
    e.DrawBorder();         
    using (StringFormat sf = new StringFormat())
    {
        sf.Alignment = StringAlignment.Center;
        sf.LineAlignment = StringAlignment.Far;
        sf.HotkeyPrefix = System.Drawing.Text.HotkeyPrefix.None;
        sf.FormatFlags = StringFormatFlags.NoClip;

        e.Graphics.DrawString(e.ToolTipText, newFont, Brushes.Red, e.Bounds, sf);
    }
}

Note: it is reproducible when using ColumnGroupsViewDefinition too.

Workaround: unpin all pinned columns before printing and restore their state after printing: