FF17: The main Function is to search for a TAB that is already opened;Right？and If you have lots of tabs opened we can use this program to search for it? or Search for a Closed tab? IF we have set it to keep Record more than 10+?
BUT IT DOESN'T WORK！ The search field doesn't even show up, nor the the rest of the thumbnails.
Oh, so you re-invented the bicycle... This all already exists in Firefox. This function is called "list all tabs" with gets turned on by about:config pref browser.allTabs.previews set to true. All the difference is that: 1. your extension opens this preview in the new tab, not above the existing one. It's actually a bad idea. 2. you've added a hotkey. This can be done using other extensions too.
You'd better spend your time at creating something that was not already done before. If you don't know what to do - I can give you some ideas.