protected override void OnResize(EventArgs e) { base.OnResize(e); // Invalidate none client area HeaderPanelNativeMethods.RedrawWindow(this.Handle, IntPtr.Zero, IntPtr.Zero, 0x0400 /*RDW_FRAME*/ | 0x0100 /*RDW_UPDATENOW*/ | 0x0001 /*RDW_INVALIDATE*/); }