I'd like to make a window stay on top of every other window (even if that other window is full-screen, has focus, and belongs to another parent). In my use case these windows are a full-screen presentation and a webcam window (to be recorded in a screencast). I think the best option is to make it a override-redirect window to force the window manager to leave it alone.
However, I don't want to change the source code of the program creating the window but use some command line tool like
xprop to do so. How do I do that?
I tried things like the following to no avail.
# xprop -id 0x5c00001 -set override-redirect 1 xprop: error: unsupported conversion for override-redirect