GGC: ForeignKeyReference relation - troubles with adding new value

I am having some troubles using Grid Grouping Control, when a cell is referrenced onto other table with RelationKind = RelationKind.ForeignKeyReference

I set relationDescriptor.ChildTableDescriptor.AllowNew = true
and
relationDescriptor.ChildTableDescriptor.AllowEdit = true

I expect user to have an ability to add new record to a parent related table.

This behaves very strange in my application now: setting allowEdit to False makes dropDown table (which is in edit mode) disappear on my click.

I also had a situation (don''t know how I did it), when dropDown table doesn''t disappear and adding new field is edited, but after closing this table, application crashes with an exception:

System.ComponentModel.Win32Exception: Error creating window handle.
at System.Windows.Forms.NativeWindow.CreateHandle(CreateParams cp)
at System.Windows.Forms.Control.CreateHandle()
at System.Windows.Forms.Form.CreateHandle()
at System.Windows.Forms.Control.CreateControl(Boolean fIgnoreVisible)
at System.Windows.Forms.Control.CreateControl(Boolean fIgnoreVisible)
at System.Windows.Forms.Control.CreateControl()
at System.Windows.Forms.Control.WmShowWindow(Message& m)
at System.Windows.Forms.Control.WndProc(Message& m)
at System.Windows.Forms.MdiClient.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.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)

I would appreciate any help to solve this problem.