🚀 go-pugleaf

Before I try out my 3 best guesses, I thought I'd ask for advice on this one:
I'd like to have a particular program plaster a big dialog box on the screen.
After the dialog is over, I'd like to get the screen redrawn properly (natch')
The problem is: suppose I've plastered that dialog over someone else's window.
The prime example is the control panel: if it's displayed when I need that 
dialog, I'd like to cover it up, but I'd also like to be able to restore it
at the end of the dialog.  The three hottest ideas I had were: 
1) When I redraw my own screen, watch the rectangle list for areas I don't
own.  Use wind_find to see who does own those areas (I presume the mouse 
doesn't actually have to be there for the wind_find to work) and send redraw
messages.
2) Open another window to contain the dialog and close it when the dialog is
done.  This should cause everyone (me included) to get redraw messages, but
I'm trying to limit the number of windows if I can.
3) Make a buffer. Save the area under the dialog, and restore it at the end
of the dialog.  How dull; how memory-hungry.

Any informed suggestions?  Other ways?  Warnings?  
                               Steve J.