User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US) AppleWebKit/532.5 (KHTML, like Gecko) Chrome/4.1.249.1064 Safari/532.5 Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 6.1; cs; rv:1.9.2.3) Gecko/20100401 Firefox/3.6.3 When You visit any detail page of comapnies listed in catalogue firmy.cz and hit shortcut: Ctrl+Shift+tab. You can see thumbnail list of opened tabs. Is it bug, that it is not working on any other pages or it is hidden prepared feature which will work in some future viersion of FF? Reproducible: Always Steps to Reproduce: 1. Visit: http://www.firmy.cz/detail/163565-multimedia-atelier-praha-podoli.html 2. Hit Ctrl+Shift+Tab with opened more tabs 3. You can see tabs thumbnails, including search box for tabs filtering in this overlay Actual Results: I get cute list of thumbnails of opened tabs - but only on this page! Expected Results: I would expect, that shortcut would work with any tab and any url opened

Being a frequent user of Ctrl-Tab and Ctrl-Shift-Tab to move forward and backward between tabs, respectively, I have seen this happen too. On most sites Ctrl-Tab and Ctrl-Shift-Tab behave as you expect them too, but in my case when checking AIM Webmail, this key combination brings up the tab thumbnails. It's very strange that the behaviour varies site-to-site. I am aware tab thumbnails were added as a "hidden" feature in Firefox 3.6 and can be enabled through about:config, but I have NOT and NEVER HAVE done this.

Added a screenshot of unexpected tab previews.

Another screenshot of this feature. With quiet different look.

I found and solution how to make it work always :) Go to about:config a find value: browser.ctrlTab.previews and set it to TRUE ... thats it ;)

Just a moment, understand that this is not a feature but a bug. Tab previews should not show up at all unless the user has turned them on through about:config. But for some reason, on certain sites, the tab previews show up on pressing Ctrl-Shift-Tab, even when the user has not turned them on. I noticed that on the AIM mail site, pressing Ctrl-Tab also jumps focus to the location bar. This is unexpected behaviour, and is therefore a bug, not a feature.

Well, I guess you are right - if users does not turn on this feature, it should not show up at all ... But my point of this issue was, that I didn`t know, that this can be turned on as default.