Force window to stay on certain workspace

Hello,

I am wondering whether it is possible to force a window to always stay
on a particular workspace. I have tried using devilspie and its
set_workspace option, but that only applies when the application is
started.

The bug I want to work around with this workspace-gluing is
https://bugzilla.mozilla.org/show_bug.cgi?id=436873 (firefox always
switching to the currently active workspace when a link is clicked in
an external application like gnome-terminal).

Any help/hints would be greatly appreciated.

With kind regards,
Jan