Starting Firefox 63, if you’ve a clean or new profile, pressing Ctrl+Tab displays preview of all open tabs by default.
Like Windows, which shows thumbnail previews of open applications when you press Alt+Tab, Mozilla has introduced a preference browser.ctrlTab.previews in about:config in Firefox 4, which when enabled shows thumbnail preview of tabs at center of browser window.
Ctrl+Tab Previews enabled by default in Firefox 63
The company has added UI option Ctrl+Tab cycles through tabs in recently used order to tabs in General under Options for the discoverability in Firefox 50. The option is disabled by default. After removing never check for updates option, Firefox team has enabled Ctrl+Tab previews by default for Firefox browsers for new profiles, this change comes into effect from Firefox 63.
bug 1473595-Enable “Ctrl+Tab cycles through tabs in recently used order” feature by default in new profiles.
Behind the scenes, Firefox sets the following about:config preferences values to true.
browser.ctrlTab.previews
browser.ctrlTab.recentlyUsedOrder
If you don’t like the change, you can disable Ctrl+Tab previews in Firefox, here is how .
Disable Ctrl+Tab Previews in Firefox
1. Click on menu
2. Select Options > General > Tabs
3. Uncheck ‘Ctrl+Tab cycles through tabs in recently used order’.
READ: Firefox 63: Disable Quick Find (for ‘ and / keys)
