WH> Herbert Rosenau wrote to Jonathan de Boyne Pollard on 12-05-1999

HR>> A window that dosn't own the focus can't receive any 
HR>> message from system queue. Bercaus PM sends this only to a 
HR>> window that owns the focus - or has to own after the focus 
HR>> change sequence (its an atomic sequence) is done.

 WH> Not true.  

True.

 WH> It will not receive mouse or keyboard messages but it sure as
 WH> heck gets WM_COMMAND and WM_SYSTEM meaasges even if hidden and/or
 WH> disabled!  

Who is forwarding them? Any window can send/post such messages to any other
window. Neither WM_COMMAND nor WM_SYSTEM are generated in system message
queue. Tey are generated by an frame window related on WM_MOUSE.../WM_CHAR
received from system message queue. You can send/post any message to any
window. So you my send/post a WM_COMMAND from any window to another to become
the action you would. 
It is usual to interact between serval windows (of serval applications) this
way.

 WH> I use non-visible (hence no focus) windows to syncronize and
 WH> dispatch message results from a network worker thread all the
 WH> time.

Yeah, Your window procedure sends it to it. It's quite legal to do so!

--- Sqed/32 1.15/development  142:
231/992
633/260
2501/209