Extensions can sometimes be the cause of problems. If the problem does not occur in Safe Mode, then you can disable your extensions one-by-one until you find out which one is causing the problem. See Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems

Thank you for your reply Chris. I'll give that a try and see what I find.

Did the checks (including disabling all plugins/themes, and resetting firefox to default settings) and the problem persists.

Your Firefox settings and info are kept in a folder separate from the Firefox program, called your profile folder. Try creating a test profile, to see if the problem still occurs. See Profile Manager - Create, remove or switch Firefox profiles

Do a clean reinstall and download a fresh Firefox copy from http://www.mozilla.com/firefox/all.html and save the file to the desktop. Uninstall your current Firefox version and remove the Firefox program folder before installing that copy of the Firefox installer. It is important to delete the Firefox program folder to remove all the files and make sure that there are no problems with files that were leftover after uninstalling.

You can skip the step to create a new profile, that may not necessary for this issue. ..... See http://kb.mozillazine.org/Standard_diagnostic_-_Firefox#Clean_reinstall

Hi,

Thanks for your suggestions. I've tried a clean install, having totally removed all traces of the previous install and profile data from both Program Files and my XP account Documents and Settings firefox/mozilla folders.

The problems persists, alas.

If the problem is not caused by something in the profile folder or program folder, then the problem is being caused by something outside of Firefox. Are your mouse drivers up to date?

Yes my mouse drivers are up to date. Everything on my clean install is up to date, and I do mean everything.

Your comment, however, got me thinking, and a couple of clicks later I discovered the precise nature of the problem. X-mouse.

With X-mouse (currently activated on Windows systems via MS's PowerToy TweakUI - previously a separate PowerToy), the menu disappears when the mouse is moved. For those who are unaware of X-Mouse, it's a tweak whereby focus always follows the mouse. Very useful for multiple windows where you don't have to click to get focus. Turning it off completely eliminates the problem.

Alas, I have personally used X-mouse for 15 years and don't much fancy turning it off just for one program that can't deal with a long established mouse control mode. I hope this can be fixed for firefox but I won't hold my breath.

Nevertheless, thanks for your assistance Chris and cor-el. It is much appreciated. At least I now know why it's happening.

I am using X-Mouse also and this is causing the problem. The Activation delay (ms) was set to zero in Tweak UI. After experimenting, I found that any delay above zero will fix the problem. Hope this does it for you too.

Thank you, thank you, thank you. I had been having the same problem for some time, and it never occurred to me that it might be related to X-Mouse. I disabled the focus tweak and now my toolbar context menus work fine. I'd have preferred not to do this, but the issue is extremely minor compared with the major trouble I was having because of not being able to access the context menus. That's where I store much of my login information for various sites. Although I could access the info through Organize Bookmarks, the process was very inconvenient. Thanks to you I'm now a happy camper.

I'm using Firefox 4 on Linux, I don't have X-Mouse, and I experience the same issue... It goes away after I restart FF, but then it eventually and inevitably comes back after some time.

I had the problem too, I have Tweak-7. It is a follow-up from 'TweakUI' special for Windows-7. This is what I did (inspired by replies in this thread): Open Tweak-7 Click Miscelaneous Tweaks In the new window click Miscellaneous Tweaks In the new window click 'Mouse Tweaks Un-check Énable window tracking using your mouse cursor Close Tweak-7 Reboot (not strictly necessary, but to be on the safe side). My problem has gone