How to send message to Desktop Widget

[marcel]

Try using postEvent instead of sendEvent. But now you won't be able to see if it was accepted. Also you need to create the events on the heap.

Regards

[high_flyer]

Here my assumption was that this code should send an "Alt + PrintScreen" button press to the desktop widget which in effect should dump the "active window image" to the ClipBoard.

In addition to what wysota said -
I don't think this assumption of yours is correct.
I would be surprized if the desktop it self was resposible for reacting to the key combination - and in this case dump a screen shot to the clip board.
I would expect it to be done by the windowing system, not by a window.