Hi,

Please check if this happens in a new profile. If the new profile is okay, you can then Reset Firefox on the old (previous) profile via Help (Alt + H) > Troubleshooting Information.

reset FF solved the problem. thanks.

Reset FF helps... For a while, then the error reappears. We need a permanent solution! I have never experienced this behavior in other versions than 13.0.1.

Some times disabling appearance extension, if any installed, in add-ons tab may solve it.

skuzt, I have tried to disable extensions, first all of them, then re-enabling one after one. In my case, Sticky password Autofill Engine 6.0.2.323 seems to be the culprit. Do you have any conclusion?

You could try to Disable or Remove it. You can also try to update. The support forum would also be helpful. You can also start a new thread which would help to provide more configuration details.

Alternatives

JohnH2O, you should address to Sticky password guys about it. It is their headache.

@skuzt: As far as I understand your answer, the Sticky extension is NOT your troublemaker? Anyway, thank you for your advice to disable all extensions and the enable one by one. To me this issue is simple, due to my curiosity I am running a trial version of Sticky; I already have Sticky Password Manager as an OEM product from another vendor (their extension is not interfering with FF 13.0.1). However, I shall inform the Sticky team. BTW, Sticky PM and FF 12.0 cooperated well.

@dumdidadida: I can assure you, the autofill add-ons are not an alternative to Sticky PM, which is a complete and very useful PM application (including autofill option).