How to detect modifier key change in a control which doesn't have focus?

Question

Background:

I\'m working on a control derived from TCustomControl class which can get focus and which has some inner elements inside. Those inner elem

Answer 1

If your control is not focused, its own key events will not be triggered. However, what you can do instead is have your control instantiate a private TApplicationEvents component internally, and use its OnMessage event to detect key events being retrieved from the main message queue before they are dispatched to any control for processing. You can then check if the mouse is over your control (better to use GetMessagePos() instead of GetCursorPos() or Screen.CursorPos so that you get the mouse coordinates at the time the messages were generated, in case they are delayed) and update your control's own Cursor property (not the Screen.Cursor property) as needed.