According to MSDN:
To get the window with the keyboard focus on the foreground queue or the queue of another thread, use the GetGUIThreadInfo function.
If I call GetGUIThreadInfo, passing 0 as a thread ID, i get the window that has the keyboard focus in the foreground thread. What I want to achieve is to know what window has the keyboard focus on NON-FOREGROUND thread. To do this, I pass the thread ID of the thread I want to "investigate", but GetGUIThreadInfo() returns all zeros. If I make that thread a foreground thread (I.E. activate the window) - then GetGUIThreadInfo() works as intended.
Is there a way to get the information I want - i.e. the window with keyboard focus that is not in the foreground thread?
EDIT: Foreground thread - a thread owning a foreground Window. Basically a thread which is attached to hardware input queue and the one which is receiving messages when I click the buttons, move mouse, etc. Likewise - non foreground thread is any thread that owns windows but is not attached to the hardware input queue.