or
'Telerik.WinControls.UI.GridFilterRowElement' is not accessible in this context because it is 'Friend'.
The Error row is:
CType(Me.RadGridView1.GetChildAt(0).GetChildAt(1).GetChildAt(1), Telerik.WinControls.UI.GridFilterRowElement).RightToLeft = True
Value cannot be null.
Parameter name: key
at System.ThrowHelper.ThrowArgumentNullException(ExceptionArgument argument)
at System.Collections.Generic.Dictionary`2.FindEntry(TKey key)
at System.Collections.Generic.Dictionary`2.TryGetValue(TKey key, TValue& value)
at Telerik.WinControls.UI.GridViewEditManager.GetDefaultEditor(IEditorProvider provider)
at Telerik.WinControls.UI.BaseGridBehavior.InitializeEditor(GridViewColumn column)
at Telerik.WinControls.UI.BaseGridBehavior.OnMouseDownLeft(MouseEventArgs e)
at Telerik.WinControls.UI.BaseGridBehavior.OnMouseDown(MouseEventArgs e)
at Telerik.WinControls.UI.RadGridView.OnMouseDown(MouseEventArgs e)
at System.Windows.Forms.Control.WmMouseDown(Message& m, MouseButtons button, Int32 clicks)
at System.Windows.Forms.Control.WndProc(Message& m)
at System.Windows.Forms.ScrollableControl.WndProc(Message& m)
at Telerik.WinControls.RadControl.WndProc(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
at System.Windows.Forms.UnsafeNativeMethods.DispatchMessageW(MSG& msg)