It would be very convenient, to have search words or strings in a list to be able to re-use them just by click. E.g. in Outlook you just click on "Search" and you'll get listed your former search strings, which can be easily used again by just a click - no input again required.
This would simplify and accelerate the search jobs for many users, dealing with hundreds of emails everyday. Is there any Thunderbird Add-On planned?