can you give me a screenshot?

Here's the screenshot. Let me know if anything else is unclear.

hmm i am sorry i cannot help there.

did this work correctly in firefox 11 & before? there was a regression with firefox not remembering positions in a dual-monitor setup (which will be fixed in firefox 14), maybe this issue is related...

To be absolutely honest, I can't ever remember a time where this worked in Firefox. I don't think the issue is related to the issue you mentioned, unless this particular issue only occurs if you have a dual-monitor-setup (I do have dual-monitors).

Firefox currently behaves differently to all native Mac apps + most Mac apps that support multiple windows.

ok, i'm not a mac user myself so i cannot test with a clean installation, but if others could reproduce this behaviour, i'd file a new bug at bugzilla.mozilla.org

I have a similar problem. The active window suddenly moves to a new workspace. This isn't something that I can duplicate, it just seems to happen at random times - it may have something to do with something I've done with the touchpad each time as it seems to be involved but I can't recreate the problem. Seriously irritating

Just for the record, I added a comment to a 2 year old (!!!!) bug: https://bugzilla.mozilla.org/show_bug.cgi?id=574229 it might have kickstarted things again, and according to the latest reports in that issue, its been fixed in firefox versions 16 and above.