After about a day of tearing my hair out, making new workspaces, reimporting projects, cleaning, cleaning, cleaning, restarting, installing updates, re-installing Flash Player, messing with my mm.cfg file, seriously considering reinstalling Flex Builder…
all in the attempt to get Flex Builder’s tracing and debugging working again…
I finally did some searches and found that FireFox’s Adblock plugin can mess this up. I had installed and activated the plugin the other day in order to test a bug someone had reported in Gravity Pods. I had even disabled the plugin after I verified the bug, but didn’t uninstall it. Sure enough, uninstalling it did the trick.
The symptoms were no tracing or debugging. Sometimes. In some projects. That was the killer part. It would work for a while, work all the time in some projects, then suddenly stop. The console would open up and immediately terminate, completely empty.
Anyway, I’m happy to have fixed it and maybe will save someone else a few hours and frustration.