For the first 9 tabs, you can make them active using Ctrl+1, Ctrl+2, etc.

Or if you are on the last tab, Ctrl+Tab will select the first tab. Etc.

I don't know whether there is a non-keyboard way to do these things...

In addition to jscher2000's solution, if it is always the leftmost tab you want, the "List all tabs" dropdown should list your tabs in the order they are placed on your tab bar (see attachment for which button I am talking about). Your leftmost tab would be the first one on the list, after the "Tab Groups" button.

Where is the List All Tabs dropdown? I tried moving the Group Your Tabs up to the right of the address bar, and FireFox closed all my Tabs, and did not even offer me a Restore All Tabs in History. So not only could I not find List All Tabs, but it also seems to have lost all my Tabs. So now I also need to know: How can I get my Tabs back?

To recover your last browsing session:

• Click on the menu button on the right side of your toolbar.
• Select History to expand the drop-down list and choose Restore Previous Session.
• Please see Restore previous session for more details

If you have overwritten that browsing session, then you may have to go to History > Show All History/View History Sidebar to find the sites you were on, assuming you weren't browsing on Private mode and don't have Firefox clearing your history.

Not sure what would have caused all of your tabs to close, clicking the "Group Your Tabs" button just puts all your open tabs in a bubble. If you close that bubble you close all the tabs inside of it, but there is an option to undo closing the group immediately after you do close it.

Unless the tab bar has been changed in Firefox 33, the dropdown menu will be somewhere to the right of your tabs, depending on how you customized your toolbar. It should look like the triangle in the screenshot I posted earlier and has nothing to do with the "Group Your Tabs" button.

For future reference, if you want to move your icons:

• Click followed by Customize
• Move the icons when on that page.

You can use Ctrl+Shift+e to view your tab groups if there isn't a tab group icon. You can close that screen by pressing Esc, or click any of the pages to view that one.

You can triple click the Tab Bar scroll buttons to go to the first tab and to go to the last tab. A double click moves the tabs across one screen width.

See also look at these prefs on the about:config page.

• browser.tabs.animate
• toolkit.scrollbox.smoothScroll

You need to close and restart Firefox after toggling these prefs.