Reproduction: 1. Create a bookmark for https://bugzilla.mozilla.org/show_bug.cgi?id=%s 2. In Bookmarks Manager, click on the bookmark, on "More", and enter in field Keyword: "bug" 3. In urlbar, enter "bug 100000" 4. In urlbar, enter "Bug 100000" Actual result (in current trunk): Step 3 goes to <https://bugzilla.mozilla.org/show_bug.cgi?id=100000> Step 4 gives an "Alert" dialog with message "The URL is not valid and cannot be loaded." Expected result (and IIRC in older builds): Step 3 and 4 match: both go to <https://bugzilla.mozilla.org/show_bug.cgi?id=100000>.
Note: You need to also set keyword.enabled = false to get the error dialog. With the default of true, "Bug 100000" does a Google search. Which is still not the expected result. Confirmed as regression. It was still working (get Expected result) with a build from 2010-07-08. I don't have builds in-between, would have to narrow down further.