Goofy behavior with Spaces

When I switch to a new Space (I have two monitors stacked on top of each other), the windows in the lower monitor move to other spaces for no apprarent reason. i.e. With Photoshop my tool windows are on the top and my workspace window on the lower monitor, and a similar setup with Illustrator, AfterFX, etc., and each of these programs set to launch in separate Spaces. I also have Spaces hot-keyed [F1] to see all the spaces at once.

Whether I jump straight to a Space or use F1 and select the Space by mouse, the lower windows are all over the place. I have to use the F1 key to view all the Spaces so I can drag the windows back to their correct Space... it's maddening.

Spaces worked fine at one time, but now it's borked. Has anyone seen anything like this before?

I am using a 2009 Mac Pro tower with a QuadroFX 4800 GPU using OSX Snow Leopard.

Thanks much,
~Chaz

No solution for you, but my issue is that I'll switch from Space 3 to Space 4 to a Finder window in order to open another file. Space 3 comes up as the file opens, but when it completes, the screen reverts back to Space 4. I understand your frustration. I seem to remember earlier times when this did not happen.