In the bug comment about that breakage on Launchpad I already explained that
I didn't break Whiteboard (or Whiteboard dialogs to be precise): it was
already broken for a very long time. I modified the build system to get rid
of link order issues, and a few left-over files re-entered the build. One of
those files even contained a syntax error and nobody noticed that. It also
had references to nonexistent object members and methods.