private void HeaderExpose(object ob, Gtk.ExposeEventArgs a) { Gdk.Rectangle rect = new Gdk.Rectangle(0, 0, header.Allocation.Width - 1, header.Allocation.Height); HslColor gcol = frame.Style.Background(Gtk.StateType.Normal); if (pointerHover) { gcol.L *= 1.05; } gcol.L = Math.Min(1, gcol.L); using (Cairo.Context cr = Gdk.CairoHelper.Create(a.Event.Window)) { cr.NewPath(); cr.MoveTo(0, 0); cr.RelLineTo(rect.Width, 0); cr.RelLineTo(0, rect.Height); cr.RelLineTo(-rect.Width, 0); cr.RelLineTo(0, -rect.Height); cr.ClosePath(); Cairo.SolidPattern solidPattern = new Cairo.SolidPattern(gcol); cr.Pattern = solidPattern; cr.FillPreserve(); solidPattern.Destroy(); } header.GdkWindow.DrawRectangle(frame.Style.DarkGC(Gtk.StateType.Normal), false, rect); foreach (Widget child in header.Children) { header.PropagateExpose(child, a.Event); } }