How to Fix Missing Bookmarks Bar, Extensions, and Buttons After Firefox Beta Update (Bug 1919721)

Firefox users with Beta and Developer Edition versions may encounter the disappearance of the bookmarks bar, toolbar buttons, and pinned extensions¹² due to bug 1919721. This issue arises from a flawed logical condition that affects toolbar management in Firefox.

Mozilla has addressed this bug in version 132.0b2³ by modifying the logical condition with gFuturePlacements.get(area)?.size⁴. However, affected users must manually adjust their preferences to restore these features. The following steps will help you resolve this issue:

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Make a copy of your profile folder before making any changes. This precaution ensures that you can revert any modifications if issues arise.

Back up and restore information in Firefox profiles

Steps to Fix the Issue

Method 1: Delete toolbar customization line (Easiest)

1. Open Firefox and type about:profiles in the address bar, then press Enter. You may see a warning; confirm your action to proceed.
2. Locate the profile that is set as "Default Profile".
3. Click on "Open Folder" next to where it shows "Root Directory".
4. In the opened directory, open prefs.js with a text editor and delete the line that starts with user_pref("browser.uiCustomization.state" (entire line).

Method 2: Restore basic toolbar elements

1. Type about:config in the address bar and press Enter. You may see a warning; confirm your action to proceed.
2. Search for the preference browser.uiCustomization.state.
3. Copy the JSON string into a text editor for easier modification.
4. Locate and modify the first occurrence of "PersonalToolbar":[] in the JSON, replacing it with:

   "PersonalToolbar":["personal-bookmarks"]
   

5. Identify and replace the contents of "TabsToolbar":[] with:

   "TabsToolbar":["firefox-view-button", "tabbrowser-tabs", "new-tab-button", "alltabs-button"]
   

6. Copy the revised JSON string back into the browser.uiCustomization.state field in about:config.
7. Click the check button to save your changes, then restart Firefox to apply these modifications.

Rearrange Icons or Restore Defaults

1. Right-click on any blank space within your toolbar and select "Customize Toolbar…" from the context menu, or navigate to View > Toolbars > Customize Toolbar… via the main menu.
2. You can either restore default configurations or manually drag and drop icons to rearrange them as per your preference.

For more details check out Customize Firefox controls, buttons and toolbars.

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By following these steps, you should be able to effectively restore and customize your Firefox Beta toolbar settings without encountering the bug-induced issue again. If issues persist after trying these methods, consider reaching out to Mozilla support for further assistance.