I would write down the list of add-ons you have and do a clean reinstall of Firefox.

Certain Firefox problems can be solved by performing a Clean reinstall. This means you remove Firefox program files and then reinstall Firefox. Please follow these steps:

Note: You might want to print these steps or view them in another browser.

1. Download the latest Desktop version of Firefox from http://www.mozilla.org and save the setup file to your computer.
2. After the download finishes, close all Firefox windows (click Exit from the Firefox or File menu).
3. Delete the Firefox installation folder, which is located in one of these locations, by default:
   • Windows:
     • C:\Program Files\Mozilla Firefox
     • C:\Program Files (x86)\Mozilla Firefox
   • Mac: Delete Firefox from the Applications folder.
   • Linux: If you installed Firefox with the distro-based package manager, you should use the same way to uninstall it - see Install Firefox on Linux. If you downloaded and installed the binary package from the Firefox download page, simply remove the folder firefox in your home directory.
4. Now, go ahead and reinstall Firefox:
   1. Double-click the downloaded installation file and go through the steps of the installation wizard.
   2. Once the wizard is finished, choose to directly open Firefox after clicking the Finish button.

More information about reinstalling Firefox can be found here.

WARNING: Do not run Firefox's uninstaller or use a third party remover as part of this process, because that could permanently delete your Firefox data, including but not limited to, extensions, cache, cookies, bookmarks, personal settings and saved passwords. These cannot be recovered unless they have been backed up to an external device!

Please report back to see if this helped you!

Thank you.

since I am apparently not deleting the Profile folder in Appdata, does that mean that all my settings in files like prefs.js, localstore.rdf and settings in about:config will be saved so I don't have to re-do those settings?

Will I have to re-install all the add-ons?

I followed your instructions with no luck. It is still doing the same thing.

Let me explain further what else is happening as I hope this will help this issue plus one other that started occurring with ver.29.

In addition to the same add-on icons just disappearing and winding back up in the "Additional Tools and Features" again, I am also experiencing a different way some, but not all, of the add-on icons are disappearing temporarily.

When I click on a link in an email or in a web page, several icons (but not all) will disappear and not show up on the new web page, but will still be on the original web page when I close the link and return to the original page.

I decided to put these icons back into the "Additional Tools and Features" section and restarted FF. Then I opened the same web page and then click on the same link. When the new page appeared, I opened Customize and went to look for the icons I had placed in "Additional Tools and Features". They were NOT there. When I closed the web page link and went back to the main web page and opened "Additional Tools and Features" the icons WERE there! Something about opening a link is causing this issue.

By the way, if I open Options/ Tabs and check "Open new windows in a new tab instead" then the above problem does not happen. Any ideas???

Which extensions are you talking about whose icons disappear?

You can check for problems caused by a corrupted localstore.rdf file.

• http://kb.mozillazine.org/Corrupt_localstore.rdf

If you do not keep changes after a restart or otherwise have problems with preferences, see:

• http://kb.mozillazine.org/Preferences_not_saved

Cor-el Priceblink, Nimbus Screenshot and the Amazon "smile" icon. (see attachment) All three disappear when opening a link and. in addition, the Amazon icon just seems to revert back to "Additional Tools and Features" for no apparent reason.

As for localstore and pres files, I have tried those in the past with no success. But if you think it would be worth trying again, which one should I try first or should I just replace both.

Create a new profile as a test to check if your current profile is causing the problem.

See "Creating a profile":

• https://support.mozilla.org/kb/profile-manager-create-and-remove-firefox-profiles
• http://kb.mozillazine.org/Standard_diagnostic_-_Firefox#Profile_issues

If the new profile works then you can transfer files from a previously used profile to the new profile, but be cautious not to copy corrupted files to avoid carrying over the problem

• http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox

Thanks Cor-el for the info. Unfortunately, even when using a new "test profile", and only installing the 3 icons above (nothing else) I got the same results. The 3 icons just disappear when I click on a link in an email for example. I'm beginning to think there must be some sort of bug with FF 29. I switched back to the default profile since the "test profile" didn't fix anything. By the way, I tried the second link (http://kb.mozillazine.org/Standard_diagnostic_-_Firefox#Profile_issues) first, but that didn't help either.

UPDATE: I've been in contact with one of the add-on developers and they tell me that they have been getting complaints from others of the same issues. Seems like a FF bug in 29 to me.

Maybe try this:

• http://kb.mozillazine.org/Prevent_websites_from_disabling_new_window_features

Thanks... I looked at the article and looked in about:config and found that the preference was already set to True so I guess that isn't the issue.

Hello,

Having exactly the same. Since the last releases ~ Firefox 24 onwards. I have on my laptop and desktop the issue that the icons of some apps disappear from the bar. I have to go into customize and put them back on the bar. This works for a moment but then the same happens those icons disappear again. The most inconvenient is the disappearing of my Multiple Gmail box checker. :-(