Trouble with input queue

[Dan Schreiber]

I'm running 2 processes on a Personal Iris v.3.3 that both use graphics
at the same time.  I'm having problems getting the correct process to 
recognize when it has control of the input queue (ie, when the mouse is
over a window controlled by that process).  Many times, the mouse is
over a window, but no input is recognized by that window.  I suspect this
is a system problem because the same thing happens in the 4sight Interface
on occasion.  Moving the mouse out of the window, and then moving it back in
always works, but I'm afraid an end user would not appreciate this extra step.
(Note: this problem occurs when the mouse is in "arrow" mode, so the solution
is not that the mouse must have been in "circle" mode, where no input is
recognized by the queue).

So my question is:  Is there a way, from within a C program, to grab control
of the input queue?  Or better yet, is there a function I can call that will
insure that input will indeed go to the window that the mouse is over?

Thanks in advance,

Dan Schreiber
dschreib at gist.com