Comment 38 for bug 124315

I don't think this should be limited to just cases where WM_WINDOW_ROLE is set. As someone else commented, virtually no applications have WM_WINDOW_ROLE set, and so only remembering window positions for apps that do set it would not really address the problem.

Also, from the docs that someone linked to on how to set the role:
http://www.pygtk.org/docs/pygtk/class-gtkwindow.html#method-gtkwindow--set-role
It says: "If a window already has a unique title, you don't need to set the role, since the WM can use the title to identify the window when restoring the session."

So I'll adjust the title of this feature request to check for WM_WINDOW_ROLE or a window title.