Strange! It sounds like the tabs are not really closing all the way.

If you go into the History menu and check the following list, do the "closed" tabs appear there:

• "3-bar" menu button > History > Recently Closed Tabs
• (menu bar or Alt+S) History > Recently Closed Tabs

Does it make any difference whether you first activate the tab (after it is restored) and allow it to load before closing it?

Tried what you said. I allowed the 3 tabs that I closed before any others to completely load. Then closed them, waited a second, and closed Firefox. Count to 5, open Firefox, and the 3 tabs I closed are there where I closed them (in this case, I've left them as the last 3 on the right). When I close them again, and continue browsing, I'll right click a bookmark on the bookmark toolbar, and choose 'open in new tab'. The tab will open after 3 blank spaces at the end. It's always the first 3 tabs, after they are closed, where the blank spaces remain. From the fourth tab and so on, the browser functions normally. BTW I have 3 pinned tabs that open on the far left of the tab bar. I'm wondering if the tab width has something to do with this anomaly. Can someone mention what the default tab width should be thru about:config Currently, counting across L to R, I have 3 pinned tabs followed by 21 1/2 tabs showing in a fully sized window. Thanks.

The default tab width ranges from 225 down to 76 pixels. When there are only a few tabs, they are at the maximum width, but as you add more tabs to the window, they progressively narrow to the 76 pixel minimum width. The minimum width can be user set as low as 50 or as high as you like, but the tabs still should disappear from the bar when they are closed.

It looks like some time back we discussed a userChrome.css file with some tab-related rules (https://support.mozilla.org/questions/1338147). If any rules are still lingering, they may need an update.

I adjusted the tab width, which I must have changed before, to the 225 & 76. Then I ended up doing a full refresh, which took awhile for my theme and add-ons. Seems like it went well, and the 3 space tabs issue is resolved. Now its just moving some extensions to the toolbar. Thanks.