/// <summary>
/// Checks if the event handler is capturing the mouse.
/// </summary>
/// <param name="handler">Event handler to check.</param>
/// <returns>True if the handler captures the mouse.</returns>
public static bool HasMouseCapture(this IEventHandler handler)
{
VisualElement ve = handler as VisualElement;
return(ve.HasPointerCapture(PointerId.mousePointerId));
}