I'd still like some help on this: Accessing menus is very slow unless I'm in safe mode. And I've tried everything I've found on the help pages.

Question

If I go in using safe mode the menus work fine. If I don't the time it takes to get the sub-menu is several minutes. I've tried "disabling the add-ons" and "resetting the controls" but that doesn't affect it. It is still slow if I'm out of safe mode. I've also tried uninstalling and reinstalling it. And I've tried deleting the "Program Files" directory it occupies in-between uninstalls and installs, too. I've also tried getting rid of Firefox and the Mozilla Maintenance Service at the same time, too, just in case. Nothing works.
I get the following error if I look at "the console": mutating the Prototype of an object will cause your code to run very slowly; instead create the object with the correct initial Prototype value using Object.create
resource://gre/components/steelApplication.js Line 783
And I've tried looking at all the other forum posts complaining about this "mutating the prototype of an object" error.
Any suggestions would be appreciated.

Answer 1

I had this problem for about a year or so. I can't remember how long I had it. I just began using safe mode all the time, so I could still use Thunderbird. I had already tried what Christ1 had recommended, too ("You can try to disable all extensions and then enable one at a time until Thunderbird starts getting slow again.").
Then one day fairly recently the problem just disappeared. I didn't do anything. I'd been upgrading Thunderbird regularly, all during the time I had the problem, too. And I'd already tried all the various solutions that had been offered on the web. It just magically disappeared one day. Oddly, I was kind of expecting that would happen. I'd just wanted it to work a lot sooner.