One thing that confused me about use % to search open tabs is that it doesn't work without a space after the %. Even worse, the top Google hit "documenting" this feature shows it without a space: https://blog.mozilla.org/theden/2012/04/30/firefox-tips-search-your-open-tabs/ Presumably it used to work? https://support.mozilla.org/en-US/questions/1046405 also omits mention of that detail. The answer at https://superuser.com/questions/1203748/how-do-i-search-open-tabs-in-firefox-natively spells it out precisely. https://support.mozilla.org/en-US/kb/awesome-bar-search-firefox-bookmarks-history-tabs doesn't even seem to mention the prefix-% thing; it describes a suffix notation that I never knew about before searching for it for this bug. (Maybe I'll switch to typing 'treeh try %' instead of '% treeh try' now? It feels a little jarring for the history results to show up first, and then get trimmed down to open tabs, but maybe it's workable.) I would request that it either Just Work, or give some indication that it is not doing the special search ("hint: if you are trying to search open tabs [or 'trying to do a % search'?], add a space after the % sign." The other punctuation operators probably ought to be handled the same way. ...though now that I know about the other way of doing it, I realize that my mental model has been wrong. The punctuation operators are separate tokens, not simply prefix operators. Then again, if you read the links above, you'll see that my misconception is very common, suggesting that it's more what people think they want, probably because we're mentally starting off with the type of search desired.