In the last few days, when I close out a tab in Firefox this often causes Flash to crash. I've sent on crash reports when this happens. Sometimes I have APIs open in a second tab and I thought there might be some interaction issue, but it's happening with totally unrelated things as well (just happened when I closed a tab with a Google map in it). Other tabs can stay open for extended periods and occasionally the game gets a bit laggy, but it doesn't crash. Only closing the tab causes the crash. When Flash crashes, the rest of Firefox (other tabs) seems fine.
Firefox 12.0 on 10.6.8 with Flash version 11.4.402.265
(I'm starting a new topic on this because it doesn't seem related to the other Firefox issues which are happening in Windows).