Modal-like dialog box without using "modal"?

[Frank Leahy]

Hi,

I have a process that creates thumbnails, and I display a dialog box 
with a progress bar while this is happening.

I want to stop the user from doing anything else, i.e. I want the 
dialog box to be "modal".  But if I make the dialog box modal, the make 
thumbnail process stops running.

My big problem is that I want to stop users bringing other windows to 
the front and clicking in those windows.  I've added a "on resumeStack" 
handler that brings the dialog box back to the front, but that doesn't 
work consistently.  I've also thought about putting a big transparent 
button on all open windows and trapping all mouse clicks, but that 
seems overkill.  Is there any way to trap all mouse clicks and key 
strokes on open windows without resorting to something like this?

How is anyone else handling this?

Thanks,
-- Frank