Did you try with Firefox in Troubleshoot Mode? https://support.mozilla.org/en-US/kb/diagnose-firefox-issues-using-troubleshoot-mode#w_how-to-start-firefox-in-4troubleshoot-modesf5safe-modesf What OS? If windows, home or pro? If windows, are you running any security software besides MS Defender? What version of Firefox?

Ok so I havent tried troubleshoot mode. I can give it a try. Using Windows 11 Pro and Firefox 140 Use Comodo Internet security 2025

Update: Looks like Its an issue with Tabmixplus. https://github.com/onemen/TabMixPlus/issues/447 Frankly only reason I now use firefox. Will downgrade. thanks for the assist.

So unsure why comment was not posted. I mentioned it it looks like the issue is incompatibility with Tabmixplus addon which is the only reason I now use firefox.

You're not alone many users have reported issues with the right-click menu after the update to version 140. It could be due to UI changes or conflicting extensions. Try resetting your context menu settings or disabling extensions one by one to isolate the cause. Hopefully, a patch is on the way soon!

You're not alone many users have reported issues with the right-click menu after the update to version 140. It could be due to UI changes or conflicting extensions. Try resetting your context menu settings or disabling extensions one by one to isolate the cause. Hopefully, a patch is on the way soon!

Hello,

Do you experience such issues? If so, you're welcome to ask a question.

After other recent updates, users affected by the "out of context items on the context menu" problem could resolve it by clearing the startup cache. That is a special way of restarting Firefox. You can find the button for it on the Troubleshooting Information page:

Use the Troubleshooting Information page to help fix Firefox issues

I don't think Firefox 140 has been out long enough to know whether that helps with the latest update.

Does deleting the start up cache loose any settings/data etc?

Does deleting the start up cache loose any settings/data etc?

I don't think so. The article linked earlier says:

Firefox stores certain temporary data in a startup cache to improve startup speed. Clearing the startup cache and then restarting Firefox can sometimes fix various issues, such as mixed languages in the user interface after an update. This will not change your profile data or add-ons.

Ok will try this after backing up. A quick question. I haven't refreshed Firefox for a long long time. Does refreshing reduce your profile folder size significantly?

The profile folder under Roaming (bookmarks, history, passwords, add-ons, cookies, local storage, etc.)? Refreshing will back up that folder to an Old Firefox Data folder on your system desktop. It will migrate selected data, such as bookmarks, history, and passwords, and not add-ons, settings, or site storage. See: Refresh Firefox - reset add-ons and settings.

If you want to reduce folder size, you could look at flushing cookies and local storage using the "Clear Data" button on the Settings page. Sometimes, these database files do not shrink that much when you empty them because disk space is preallocated in chunks. If you have lots of time, and need to recover as much space as possible without the full Refresh, you could go into the storage folder on disk and delete folders for sites you don't care about.

Thanks. I did refresh but also kept a copy of the original in case I want to go back. I find its not much of saving really. It started off with 200-300mb and reset all personal settings not just the add-ons etc which sucks. Kept updating to 140 with reset of setting to autoupdate. Brilliant - not. Anyway after the third time managed to get everything addon wise installed after stuffing up a few times including customizing the bar etc. Well not worth it at all really when it balloons to 900mb right off the bat.

One thing I could not fix is the bookmarks/menu items have significant spaces between each line/option. Frankly Tab Mix Plus features should be incorporated into Firefox in my opinion.

One thing I could not fix is the bookmarks/menu items have significant spaces between each line/option.

Were you using Compact Mode before? You can set that using this approach:

(1) In a new tab, type or paste about:config in the address bar and press Enter/Return. Click the button accepting the risk.

More info on about:config: Configuration Editor for Firefox. The moderators would like us to remind you that changes made through this back door aren't fully supported and aren't guaranteed to continue working in the future.

(2) In the search box in the page, type or paste browser.uidensity and pause while the list is filtered

(3) Double-click the preference to display an editing field, and change the value to 1 then press Enter or click the blue check mark button to save the change.

Frankly Tab Mix Plus features should be incorporated into Firefox in my opinion.

Which features? Some of them are probably part of Firefox but could be hard to find.

Were you using Compact Mode before? You can set that using this approach: (1) In a new tab, type or paste about:config in the address bar and press Enter/Return. Click the button accepting the risk. More info on about:config: Configuration Editor for Firefox. The moderators would like us to remind you that changes made through this back door aren't fully supported and aren't guaranteed to continue working in the future. (2) In the search box in the page, type or paste browser.uidensity and pause while the list is filtered (3) Double-click the preference to display an editing field, and change the value to 1 then press Enter or click the blue check mark button to save the change.

Frankly Tab Mix Plus features should be incorporated into Firefox in my opinion.

Which features? Some of them are probably part of Firefox but could be hard to find.

Oh thanks for that I will activate it. To go along with it I also changed this in about:config

toolkit.legacyUserProfileCustomizations.stylesheets to true which compacted the menus/bookmarks and fixed it for me. Unsure if this by itself does this since I did copy over some config files from my old data. Maybe from here https://github.com/MrOtherGuy/firefox-csshacks

Tab Mix plus really has a lot of customisations I like. Ability to change the behavior according to your needs is key I believe which either makes or breaks the experience. Multi line tab rows, Tab opening, closing event actions etc. Frankly a huge list of options https://onemen.github.io/tabmixplus-docs/help/introduction/

I can even save and restore those settings which is a plus. I mean firefox itself has no backup option for settings etc. I only see a sync option to sync all firefox browsers on multiple devices I use under the account. I mean this 2025. Do I really want to keep setting it up after a refresh, waste of time really......lol sorry rant over.

Hello

To complement, this discussion, by way of another illustration.

It seems crazy that Firefox does not have the ability to set new tabs to be any URL that I want.

https://support.mozilla.org/en-US/questions/1480324

Hello To complement, this discussion, by way of another illustration.

It seems crazy that Firefox does not have the ability to set new tabs to be any URL that I want.

https://support.mozilla.org/en-US/questions/1480324

Yeah it seems rather weird that all these companies are either clueless or have bad managers in high places making stupid decisions. Few examples

Win 11 - Needs startallback or similar for visual and functional customisations. I even have to get into regedit to make some other changes I need in this day and age. What happened to using GUI to provide all options?

Firefox - Needing all these addons to achieve what I need to make my experience the best it can be.

Could go one but you get the picture.

Open source is cool, because, is fun.

About compact mode, take a look at this parenthesis https://connect.mozilla.org/t5/discussions/fully-support-web-usb-and-web-serial/m-p/48852/highlight/true#M17524 in this subject

Firefox advanced customization and configuration options https://support.mozilla.org/en-US/kb/firefox-advanced-customization-and-configuration