My window manager of choice is xmonad and I am very happy with it. However, I am learning to develop applications using Gtkmm and Glade, and for this very specific purpose and nothing else, I would like to have a "normal" non-tiling window manager. I think the best compromise (if it is possible, of course), would be to run the non-tiling window manager inside an xmonad tile. How could I do this?
There is an application called xnest which allows you to nest an X11 server within a window of another X11 server... Don't know how deep you can go before you figuratively "cross the beams"... but still...
You might look into that. I've used it a long time ago to play with other WM's from my default setup. No guarantees though.