This is a recently introduced space saving measure. The close buttons appear if you click the tab.

I do not know if there is any addon that will reverse this, or any easy method of re-introducing it but it is not something I mind. My reply is to let you know it is not a fault and for instance it is not caused by some extension you have so will not change back when you try safe mode.

Dear John99, it's very simple and very useful answer. I almost broke my head with this issue and the answer was so simple. I have tons of tabs opened at one session. :-) Thank you.

You may find the tab grouping feature useful. It may be convenient to use more than one Firefox window if you have loads of open tabs.

• Use Tab Groups to organize a lot of tabs

Please however take care because

• Many tabs open could slow down Firefox
• Do not rely only on the open tabs.

The whole restore system it is based on is slightly fragile and does not have any good backup system. Consider making sure you bookmark the important tabs that you have open. Then even if you are not able to restore to the state it was in at least the page may be found.

I'm still seeing close buttons on all tabs with browser.tabs.closeButtons = 1 unless there are many tabs open.

You can also look at the browser.tabs.tabClipWidth pref (close and restart Firefox after modifying this pref).

• http://kb.mozillazine.org/browser.tabs.tabClipWidth
• http://kb.mozillazine.org/browser.tabs.closeButtons

Start Firefox in Safe Mode to check if one of the extensions (Firefox/Tools > Add-ons > Extensions) or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox/Tools > Add-ons > Appearance).

• Do NOT click the Reset button on the Safe Mode start window.

• https://support.mozilla.org/kb/Safe+Mode
• https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes

In this case screenshot was of a lot of tabs open.

Thank you for this advice about using Groups. It's very nice. But there are some inconveniencies as for me: 1) All of the Grpoups are opened at the same time. There is no possibility to save Groups as Bookmarks for later opening. 2) You can loose control on amount of opened tabs, so FF will use a lot of memory. In my case it is almost 900 MB with 3 Groups.

Dear cor-el "You can also look at the browser.tabs.tabClipWidth pref (close and restart Firefox after modifying this pref).

   http://kb.mozillazine.org/browser.tabs.tabClipWidth "

I made use of your advice and now I have x-botton on every tab regardless the amount of open tab. Thanx a lot.

You're welcome