void HeaderButtonRelease(object ob, Gtk.ButtonReleaseEventArgs args)
{
if (args.Event.Button == 1)
{
frame.DockInPlaceholder(item);
frame.HidePlaceholder();
if (header.GdkWindow != null)
{
header.GdkWindow.Cursor = handCursor;
}
frame.Toplevel.KeyPressEvent -= HeaderKeyPress;
frame.Toplevel.KeyReleaseEvent -= HeaderKeyRelease;
}
}
