Maybe there is any fix for it or some idea about what software can cause this? Looks like it has one source with the lag-bug, which hangs QL for a 2-3 secs? It's so annoying that time to time it happens. And maybe it's going to happen more often!?

Please, can you fix this at least? I'm running Firefox , Mac OS 10.7.4. And it seems that this misery bug was not here forever, it started after some update, but I'm not sure in this info..