To reproduce
Switch to Right-to-Left mode.
Look at the top left corner of the grid.

Workaround
this.radGridView1.TableElement.Children[0].Margin = new Padding(-2, 0, 0, 0);

GridViewMultiComboBoxColumn accepts only valid values according to the specified ValueMember. By entering "A" in the RadMultiColumnComboBoxElement editor in the filter cell, you can not filter the main RadGridView with all cells that starts with "A" as "A" is not a valid value according to the GridViewMultiComboBoxColumn.ValueMember property.  

Workaround: The ContextMenuOpening can be used to hide the irrelevant filter members

To reproduce:
-add hierarchical RadGriddView with one parent template and several child templates;
-set TableElement.PageViewMode to PageViewMode.ExplorerBar;


Selection for different templates is not performed correcltly.


Workaround: use custom GridDataRowBehavior:


BaseGridBehavior gridBehavior = this.radGridView1.GridBehavior as BaseGridBehavior;
            gridBehavior.UnregisterBehavior(typeof(GridViewDataRowInfo));
            gridBehavior.RegisterBehavior(typeof(GridViewDataRowInfo),
                new RowSelectionGridBehavior());


public class RowSelectionGridBehavior : GridDataRowBehavior
{
    protected override bool OnMouseDownLeft(MouseEventArgs e)
    {
        GridDataRowElement row = this.GetRowAtPoint(e.Location) as GridDataRowElement;
        if (row != null)
        {
            row.RowInfo.IsSelected = true;
            row.RowInfo.IsCurrent = true;


            return true;
        }


        return base.OnMouseDownLeft(e);
    }
}

Workaround:  this.radGridView1.XmlSerializationInfo.SerializationMetadata.Add(typeof(GridViewSummaryItem), 
                "AggregateExpression", DesignerSerializationVisibilityAttribute.Content);

Workaround: custom RadGridViewDragDropService and an override of the HandleMouseMove method, please check the attached project

The control just does not appear in the destination solution.

To reproduce:
- Open the hierarchy example in the demo application.
- Select Auto-GenratedDataSet and add a new row in the third level template.
- Select Manually generated for Bound Mode and then re-select Auto-GenratedDataSet
- Try to add new row again. Yo will notice that the new row is not added.

Workaround:
class MyNewRowBehavior : GridNewRowBehavior
{
    protected override bool ProcessEnterKey(KeyEventArgs keys)
    {
        if (this.GridControl.IsInEditMode)
        {
            GridViewSynchronizationService.SuspendEvent(this.GridControl.CurrentRow.ViewTemplate, KnownEvents.CurrentChanged);
            bool result = base.ProcessEnterKey(keys);
            GridViewSynchronizationService.ResumeEvent(this.GridControl.CurrentRow.ViewTemplate, KnownEvents.CurrentChanged);
            return result;
        }
        else
        {
            return base.ProcessEnterKey(keys);
        }
    }
 
    protected override bool ProcessTabKey(KeyEventArgs keys)
    {
        if (this.GridControl.IsInEditMode)
        {
            GridViewSynchronizationService.SuspendEvent(this.GridControl.CurrentRow.ViewTemplate, KnownEvents.CurrentChanged);
            bool result = base.ProcessTabKey(keys);
            GridViewSynchronizationService.ResumeEvent(this.GridControl.CurrentRow.ViewTemplate, KnownEvents.CurrentChanged);
            this.Navigator.SelectNextColumn();
 
            return result;
        }
        else
        {
            return base.ProcessTabKey(keys);
        }
    }
}

The default behavior can be changed as follows:
((BaseGridBehavior)radGridView1.GridBehavior).UnregisterBehavior(typeof(GridViewNewRowInfo));
((BaseGridBehavior)radGridView1.GridBehavior).RegisterBehavior(typeof(GridViewNewRowInfo), new MyNewRowBehavior());

How to handle this case:

Subscribe to the CellValidating event and add logic for validation. For example:

If e.Value Is Nothing Then
    e.Cancel = True
End If

Additionally you can handle the DataError event to handle cases where users are trying to submit invalid data through the grid to its data source.

Finally, you can subscribe to the ContextMenuOpening event where to hide the "Clear value" item from context menu with following code snippet:

For i As Integer = 0 To e.ContextMenu.Items.Count - 1
    If e.ContextMenu.Items(i).Text = "Clear Value" Then
        e.ContextMenu.Items(i).Visibility = Telerik.WinControls.ElementVisibility.Collapsed
    End If
Next

The GridTimePickerEditor format is not correctly taken from the GridDateTimeColumn FormatString property.

Workaround: 
Use the Format and CustomFormat properties.

To reproduce:

Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load 
    Me.CustomersTableAdapter.Fill(Me.NwindDataSet.Customers) 
    Dim view As New ColumnGroupsViewDefinition()
    view.ColumnGroups.Add(New GridViewColumnGroup("Customer Contact"))
    view.ColumnGroups.Add(New GridViewColumnGroup("Details"))
    view.ColumnGroups(1).Groups.Add(New GridViewColumnGroup("Address"))
    view.ColumnGroups(1).Groups.Add(New GridViewColumnGroup("Contact"))
    view.ColumnGroups(0).Rows.Add(New GridViewColumnGroupRow())
    view.ColumnGroups(0).Rows(0).Columns.Add(Me.RadGridView1.Columns("CompanyName"))
    view.ColumnGroups(0).Rows(0).Columns.Add(Me.RadGridView1.Columns("ContactName"))
    view.ColumnGroups(0).Rows(0).Columns.Add(Me.RadGridView1.Columns("ContactTitle"))

    view.ColumnGroups(1).Groups(0).Rows.Add(New GridViewColumnGroupRow())
    view.ColumnGroups(1).Groups(0).Rows(0).Columns.Add(Me.RadGridView1.Columns("Address"))
    view.ColumnGroups(1).Groups(0).Rows(0).Columns.Add(Me.RadGridView1.Columns("City"))
    view.ColumnGroups(1).Groups(0).Rows(0).Columns(1).RowSpan = 40
    view.ColumnGroups(1).Groups(0).Rows(0).Columns.Add(Me.RadGridView1.Columns("Country"))

    view.ColumnGroups(1).Groups(1).Rows.Add(New GridViewColumnGroupRow())
    view.ColumnGroups(1).Groups(1).Rows(0).Columns.Add(Me.RadGridView1.Columns("Phone"))
    view.ColumnGroups(1).Groups(1).Rows(0).Columns.Add(Me.RadGridView1.Columns("Fax"))

    RadGridView1.ViewDefinition = view
    Dim summaryItem As New GridViewSummaryItem()
    summaryItem.Name = "Address"
    summaryItem.Aggregate = GridAggregateFunction.Count
    Dim summaryRowItem As New GridViewSummaryRowItem()

    summaryRowItem.Add(summaryItem)
    Me.RadGridView1.SummaryRowsTop.Add(summaryRowItem)
    Me.RadGridView1.MasterView.SummaryRows(0).PinPosition = PinnedRowPosition.Top
    Me.RadGridView1.MasterView.SummaryRows(0).Height = 20
End Sub


Workaround: use the ViewCellFormatting event and set the TextAlignment property to MiddleTop for the summary cells.

1. Load the ControlDefault theme in Visual Style Builder
2. Edit the cell style and try to disable the cell border when RadGridView is not focused and the HideSelection property is set to true.
3. You cannot because the HotTracking property is not updated correctly for grid cells.

Workaround: 
void radGridView1_CellFormatting(object sender, CellFormattingEventArgs e)
{
    if (e.CellElement.IsCurrent && !e.CellElement.RowElement.HotTracking)
    {
        e.CellElement.DrawBorder = false;
        e.CellElement.DrawFill = false;
    }
    else
    {
        e.CellElement.ResetValue(LightVisualElement.DrawFillProperty, ValueResetFlags.Local);
        e.CellElement.ResetValue(LightVisualElement.DrawBorderProperty, ValueResetFlags.Local);
    }
}

For now you can manually add the columns to the ExcelFilteredColumns collection when the filters are added in code:

FilterDescriptor fd = new FilterDescriptor("Value", Telerik.WinControls.Data.FilterOperator.IsEqualTo, "B");
fd.IsFilterEditor = true;
radGridView1.FilterDescriptors.Add(fd);

this.radGridView1.MasterTemplate.ExcelFilteredColumns.Add( this.radGridView1.Columns[0] );   

ADD. RadGridView - add export of ViewDefiniton

1. Add export functionality for ColumnGroupsViewDefinition 
2. Add export functionality for HtmlViewDefinition 

Currently each grid is exported in a separate excel file with one or more sheets. It will be good to add the possibility to export a grid to a separate sheet in an existing file.

Add the ability to print all levels of a hierarchical RadGridView.

When exporting to HTML or PDF image columns should be exported properly.

WORKAROUND:

The format of the file that ExportToExcelML creates is ExcelML which is an extended XML. If you do not want to receive the message, you have to change the extension of the file to ".xml". Even though the file will have an xml extension, it will still be associated with MS Excel and will be opened by Excel.There is a possibility to turn this warning message off on the client machine. You can read more about that on the following blog post - Excel 2007 Extension Warning On Opening Excel Workbook from a Web Site (http://blogs.msdn.com/b/vsofficedeveloper/archive/2008/03/11/excel-2007-extension-warning.aspx)

Another workaround is to use Interop to open the file and excel and save it in XLSX format. However, this would require Administrator or Power User  (http://msdn.microsoft.com/en-us/library/ms173186%28v=vs.80%29.aspx). A reference from COM to the corresponding office version should be added. Here is the code for saving:

    ExportToExcelML exporter = new ExportToExcelML(this.radGridView1);

    exporter.ExportVisualSettings = true;

    string tempPath = Path.GetTempPath();

    tempPath += "tempgrid.xls";

    exporter.RunExport(tempPath);

    Microsoft.Office.Interop.Excel.Application app = new Microsoft.Office.Interop.Excel.Application();

    if (app == null)

    {

        Console.WriteLine("EXCEL could not be started. Check that your office installation and project references are correct.");

        return;

    }

    app.Visible = false;

    app.Interactive = false;

    Microsoft.Office.Interop.Excel.Workbook wb = app.Workbooks.Open(tempPath);

    string desktopPath = Environment.GetFolderPath(Environment.SpecialFolder.Desktop);

    desktopPath += "\\grid.xlsx";

    wb.SaveAs(desktopPath, Microsoft.Office.Interop.Excel.XlFileFormat.xlWorkbookDefault);

    wb.Close();

    app.Quit();

    Marshal.ReleaseComObject(wb);

    Marshal.ReleaseComObject(app);

    File.Delete(tempPath);

Transfer the pinned status of grid's columns and rows to the exported excel file.

Add Page format functionality (like header, footer, page number) when you export a RadGridView to pdf similar to RadPrintDocument.
http://www.telerik.com/help/winforms/tpf-printing-support-radprintdocument-header-and-footer.html

Currently all exported cells are static.