Sometimes when you open so many tabs, you may find it hard to move back to the last selected tab because of the distance caused by the overwhelming number of tabs that separate it from the current tab. Installing extension like Tab Mix Plus and set it to display multiple tab bars can help a little but, again, it still depend on the number of opened tabs.
There are a couple of ways to overcome this problem. You can make use of the built-in feature in Firefox or use an extension.
Enable Ctrl+Tab Preview
Open about:config, type browser.ctrlTab.previews and double-click on it to change the value to true
Enabling this feature will allow you to open the last selected tab by pressing Ctrl+Tab.
If you press and hold Ctrl+Tab, a thumbnail list of the six last recently used tabs will open. Below the thumbnails is the option to access the “List All Tabs” menu if you want to open another tab that isn’t included in the MRU list.
Note that the activation of this feature will also change the default behavior of Ctrl+Shift+Tab—instead of going backwards, it opens the “List All Tabs”.
When you’re in the thumbnail list, pressing Ctrl+Shift+Tab will still select the previous tab anyway.
More Last Used Tabs with SuperTab
Restartless SuperTab extension displays the MRU list in flat style. By default it contains 20 last selected tabs in MRU order. More tabs can be added via its Options page.
The extra feature optionally sets the browser to focus on the last selected tab when current tab is closed.
Add Customizable Shorcut to Move Between Two Last Selected Tabs
If you just need a shortcut that allows you to quickly move to the last active tab, perhaps you will find Last Selected Tab extension to be sufficient. This restartless add-on provides nothing else but the ability to define your own hotkey for the simple purpose.
The good thing about the add-on beside its simplicity is that it doesn’t change the default behavior of Ctrl+Tab. You can still use it to go to next tab while having another configurable shortcut to switch to the last recently used tab.
From the above solutions, I prefer using the third. It’s simple and it leaves Ctrl+Tab untouched. What’s your choice? Or do you have any other option?