Compilation window in other frame only

[Martin]

I like to have two frames in my programming sessions: one with a few
windows with source files, and one (on a second monitor) with the
compilation buffer. However, even if I have a second frame with the
*compilation* buffer open, Emacs opens a new window in the "source
file frame" with another copy of the compilation buffer. I think it
wasn't like this earlier. Then, Emacs didn't open a new window if
there was one already open in another frame. I'm using GNU Emacs
23.0.60.1 now. How can this behaviour be controlled?