Winit Backend: Created an EventResult::Retarget(_) to allow event handlers to send events to other windows

[npwoods]

This allows Custom Application Handlers and Window-specific event filters to cause events to be dispatched to other windows. When this is done, the two types of handlers will be reinvoked.

[ogoffart]

Could you elaborate on what is the usecase for this feature?

[npwoods]

In my case I create my own child window with winit outside the purview of Slint (I submitted a hook earlier #8150 which got correctly obsoleted by the newer CustomApplicationHandler infrastructure). I don't have control over the logic attached to this window, but I do have (again with CustomApplicationHandler) access to the events.

For things like menu shortcuts to work properly, I need to retarget some events to the Slint window.

I'm open to the possibility that there might be a better way to do this. In my case changing the WindowId is sufficient, but I could see a more flexible solution being a facility to modify the event in its entirety. Your call.