Firebug and Live HTTP Headers have both been known to cause this, see:
https://www.mozdev.org/bugs/show_bug.cgi?id=19262 https://bugzilla.mozilla.org/show_bug.cgi?id=479778
Since comment 2 suggests this happens in safe mode, let's ignore those potential causes?
This could also be a dupe of bug 459384.
Firebug and Live HTTP Headers have both been known to cause this, see:
https:/ /www.mozdev. org/bugs/ show_bug. cgi?id= 19262 /bugzilla. mozilla. org/show_ bug.cgi? id=479778
https:/
Since comment 2 suggests this happens in safe mode, let's ignore those potential causes?
This could also be a dupe of bug 459384.