The complaints mainly came from users with older computers, which were seeing the game crash from within their browser due to Firefox's update.
How "Crash Protection" works, explains Mozilla, is if Flash, QuickTime or Silverlight crash or become unresponsive for over 10 seconds, the browser kills the plug-in.
Users with older computers say the 10-second rule is too short, as they normally have 30 seconds or more of non-responsiveness, when playing any games requiring a plug-in.
Says Mozilla: "Following the release of Firefox 3.6.4 we heard from some users, mainly those using older computers, that they sometimes expect longer periods of non-responsiveness from plug-ins, especially with games. For these users, the default timeout of 10 seconds was too short."
The new update bumps the termination period to 45 seconds.
Bugzilla, Mozilla's bug-tracking database says complaints mainly came from Farmville players.
"Now that (Firefox) 3.6.4 has shipped, we are seeing an increasing number of reports that some users are unable to play Farmville, because Farmville hangs the browser long enough for our timeout to trigger and kill it," adds Mozilla developer Justin Dolske. "Let's hit this with a big hammer and make it 45 (seconds)."