DockableFrameFocusChanged

Hi.

We are experimenting Problems with DockablePanes, the reason is a misbehavior in the event UIControlledApplication.DockableFrameFocusChanged.

It used to work properly in version 2016, but unfortunately in version 2017 it is simply never raised by revit application.

application.DockableFrameFocusChanged += new EventHandler<RvtUI.Events.DockableFrameFocusChangedEventArgs>
((sender, e) =>
{
   // Do something

});

could you provide some help?