I noticed the same thing, but I seem to have stumbled onto a different workaround:
1) Go to OS Window view mode and put the window on the screen you want.
2) Go into Coherence Mode
3) Once in Coherence Mode, select the View->Full Screen mode
This seems to work for me most of the time; sometimes it hasn't worked but I haven't done an exhaustive test since I'm tending to use Coherence mode more often now.
Don't know if it matters or not, but I have my Coherence settings set to "Use multiple displays" (View->Customize->Coherence tab).
Hope this helps ... one other thing I noticed is this workaround seems to work most reliably if I enter Coherence Mode through the View menu, rather than the little Coherence icon. (I think ... hard to be sure, though.)
Last edited: Dec 22, 2006