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Everytime I close a Firefox window (FF3.6) I get a popup with the message

"We're sorry, there was an error. Description: getMainWindow() is null occurred when we did: OnTabSelect on line:144".

I have to click "OK" before I can do anything else with Firefox. I have tried googling the message with no joy.

Could somebody please explain. Thank you.

2010-03-04 20:33:00
In a display of unmitigated lese-majesty the pop up returned after my above posting of thanks to Taty so I went through the business with the plugins again, this time with no effect. And so, girding my loins, I looked to other alternatives, first changing my theme,no joy, and then, after a night's sleep, set to checking my addons. Now I freely admit to being a total addon slut, I've never seen one I didn't want, so this was no minor task but I persevered and after what seemed like, but in all probability wasn't, a fortnight or so I discovered the problem could be dealt with by disabling an addon called 'New Tab King'. Please note, I DO NOT state that the problem was caused by 'New Tab King' merely that in my configuration of multitudinous addons some combination involving it did so. If someone were to design a programme that could check out every possible combination of addons in something less than geological epochs I could probably discover the root cause.Nevertheless, I still proffer my thanks as above as testing my addons was a logical extension of checking my plugins and the right result obtained in the end,roger.
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Taty
2010-03-03 18:43:00
You might also have some plugin installed that is causing the problem. Try disabling all the plugins and see if it still happens. If not, then re-enable one by one to find out which one is causing the problem.
2010-03-04 00:50:00
I followed your advice and disabled all my plugins and lost the pop up. I then re-enabled one by one and, strangely, the pop up never reappeared so, somehow, it did the trick and I'll have some idea what to do if it ever reappears. Thank you very much for your time and assistance, roger.
Taty
2010-03-04 06:21:00
Very glad I was able to help, Roger :)
2010-03-03 05:18:00
If you are using a Mac, open Firefox, click on Preferences from the tab menu :) You can disable the pop up by unclicking the box :)
2010-03-04 00:52:00
I'm using Windows 7 but thanks anyway, roger