public override void OnApplyTemplate() { _expansionButton = this.GetTemplateChild("PART_ExpansionButton") as Arc; if (_expansionButton != null) { _expansionButton.AddHandler(RadialMenuExtensionButton.MouseEnterEvent, new MouseEventHandler(this.OnMouseEnter)); _expansionButton.AddHandler(RadialMenuExtensionButton.MouseLeaveEvent, new MouseEventHandler(this.OnMouseLeave)); _expansionButton.AddHandler(RadialMenuExtensionButton.MouseLeftButtonUpEvent, new MouseButtonEventHandler(this.OnMouseLeftButtonUp)); } }