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Why does Firefox sometimes put the New Tab "+" button to the left of my tabs instead of the right?

  • 9 bhfreagra
  • 17 leis an bhfadhb seo
  • Freagra is déanaí ó cor-el

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In some windows, Firefox puts the New Tab "+" button to the left of my tabs instead of the right. This seems to be more likely to happen when it re-opens windows from a previous session (not sure that's always true). In the window I'm typing this, the + tab button is to the left of my tabs, but if I open a new Firefox window, it is correctly to the right of the tabs.

Also, even in a window that incorrectly places the + tab button to the left of the tabs, when I go into Customize mode, it immediately and correctly shows it on the right. As soon as I close the "Customize Toolbar" window, it bounces back to the left edge.

As you can imagine, any button appearing in different places in different windows or at different times is annoying and breaks the UX. I also worry this may be a symptom of some more serious problem, though everything else appears to still work, even in those windows where the new tab button is in the wrong place.

Why does this happen and can I stop it? I have seen nothing about this posted here, but I've had this problem at least since version 12, and it's still happening in 13.0.1. I have the same problem on multiple computers, including after new installs. I don't use many add-ons -- LastPass, XMarks... I think that's it.

<This may be a duplicate post -- I thought I posted this earlier this morning, but after creating and confirming my new account to post to the forum, it never appeared, so now re-posting. Apologies if there is just a long lag and both appear. I think this is the more detailed posting though.>

Athraithe ag WebColin70 ar

All Replies (9)

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You can try to move the + icon around and place it on the far right again when in the [Customizing Customize] mode. You can also try to Reset toolbars and controls: and Make Changes and Restart in the Safe Mode start screen. Alternatively you can try to delete localstore.rdf in the Firefox Profile Folder. You can also open the profile folder via Firefox Help (Alt + H) > Troubleshooting Information > Show Folder.

Firefox Profile Folder & Files

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I do not believe this is related to the Customization options. In general use, including, I think, all new windows even when existing open windows are wrong, the + tab button appears correctly on the right. Also, as noted in my original description, I can't move it to the right in the Customization Toolbar window, because as sign as I enter that mode, the + tab jumps to the right (as if Firefox thinks it is on the right, or at least knows that's the setting), only to move back to the left as soon as I close it.

This is clearly a bug, I just don't have enough information to provide 100% certain steps to reproduce, and it seems no one here has a work-around yet.

This appears to be a problem relating to restoring windows previously open. It also seems to be related to having a large number of tabs open, though I'm even less certain of that (nor if it matters how many tabs per window). It seems to me that it is much more likely to happen if when I launch Firefox, it has to restore 20+ tabs. I don't notice the problem in conservative use of Firefox for a few hours with only a few tabs open.

Thanks, Colin

Athraithe ag WebColin70 ar

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I think I might have a work's worked for the last hour, anyways. I had the same issue where my new tab button would migrate from left to right depending on how many tabs I had open at any given time

Open the customize toolbar and insert a "flexible space" between the new tab button on the right and the last open tab. This should lock the new tab button to the right side of the page.

Good Luck!

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This may be related to session restore.

  • bug 774943 - Session restore puts "+" button in the wrong spot and hides first tab
  • bug 714382 - Leftmost tab is hidden when reopening browser window

(please do not comment in bug reports)

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cor-el, yes, the first (bug 774943) EXACTLY describes the behavior. The second bug appears to be the same issue and also matches my experience. In my case, my Firefox is set to automatically restore the previous session, so for me, the behavior happens automatically at restart.

I see both of these bugs are marked as UNCONFIRMED. How do we get Mozilla to recognize that these are true bugs?

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soraya.sayu, for me, this never happens mid-session. My issue only occurs when restoring a session. I have added the flexible space. I don't like this workaround, because it takes away space from my tabs, but I'll try to monitor if it helps. Hard to test, because I cannot reproduce it 100% of the time, and it seems most likely to happen when Firefox crashes with a couple of dozen or more tabs open across multiple windows.

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A possibly corrupt localstore.rdf file due to a crash, or other external factors like interference (AV, other software etc.) may also cause this.


If it is happening even otherwise, please also try the Reset Firefox feature via Help (Alt + H) > Troubleshooting Information.

(To revert to the previous profile you were using, close the new profile (i.e. exit Firefox), start Firefox and choose the Default User profile. While the Profile Manager is open, you can also delete the newly reset profile (the one containing random numbers), or the former profile, as the case may be). If the reset is okay, it would be a good idea to delete the old profile as otherwise it would be left intact with the previous data/cache until deleted.

Managing profiles

Profiles Howto

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I experienced exactly the same problem today. FF 15.0. Three windows, 58 tabs overall. At some point, after relaunching FF and restoring the previous session some of the windows got the "+" Add New Tab button on the left of the Tab Bar, with the leftmost tab hidden (but still accessible via Ctrl+Tab).

The weird thing, simply closing FF and later restoring the session again produced random results. I.e. the "+" button placement could stay the same as before, or the button could change its placement in some windows, or it could even move to its proper placement at the right of the Tab Bar with the leftmost tab become visible again.

bug 774943 seems totally related to what i experienced.

For me, restarting FF in Safe Mode fixed the problem. So, after some trials and errors, i found out that disabling the "Google Search by Image" addon fixed the problem. Hope it helps somebody.

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It is probably best to create a new profile folder to fix this issue.
I had it with a rather old profile that has been used with a lot of Firefox versions, but didn't succeed in finding a cause of the problem.

See "Creating a profile":

You can transfer some files from the old profile to that new profile, but be careful not to copy corrupted files.