System Modal Dialogs

X11 has a ‘system modal’ mode in which ALL windows are blocked except a single dialog. Photon’s modal dialogs will block the application’s windows, I need to block ALL windows in all applications.
Any clues on how to do this?

It’s all in placement. You want your application out front. Behind your application, you want to put a region that is opaque to input, but transparent to output. The details are a bit muddy, but you might want to take a look at a the source to a screen saver.

That’s the direction I’ve been trying. So far I can get the region where I want it (verified with phview) and it’ll block some events. But (for example) I can’t get it to block window manager stuff, i.e. when I click on a different apps window which is ‘underneath’ my special region, that window always pops to the front.

So what’s the magic for blocking these events?