User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.1.5) Gecko/20091102 Firefox/3.5.5 (.NET CLR 3.5.30729) Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.1.5) Gecko/20091102 Firefox/3.5.5 (.NET CLR 3.5.30729) Page is bookmarked, unintentionally, when you want to switch to different application on windows. Reproducible: Always Steps to Reproduce: 1. Open a web page. Bookmarks->Bookmark this page (or Ctrl+D). Don't click anywhere. 2. Press alt+tab. Or just click to a different window (firefox window also). 3. The page is bookmarked, even if you didn't click on "Done". Expected Results: If you don't click on "Done" it should not bookmark any page.

Thanks for the report. This is a duplicate of Bug 445279. See https://bugzilla.mozilla.org/show_bug.cgi?id=445279#c2. Looks like it is scheduled to be changed.

Ok, I didn't find that bug. Funny, that something that looks like it should be fixed easily, is not fixed even after more than a year (and is still moved from version to version).