Won't this result in many unwanted page if you have a folder with a common word? Maybe applying search to folders only when search with operator like folder:foo is better. No?

Is it a duplicate of bug 406157 ? https://bugzilla.mozilla.org/show_bug.cgi?id=406157

the request is the same, and there we have more informations, so even if this is older i'm duping to that.

Bug 451915 - move Firefox/Places bugs to Firefox/Bookmarks and History. Remove all bugspam from this move by filtering for the string "places-to-b-and-h". In Thunderbird 3.0b, you do that as follows: Tools | Message Filters Make sure the correct account is selected. Click "New" Conditions: Body contains places-to-b-and-h Change the action to "Delete Message". Select "Manually Run" from the dropdown at the top. Click OK. Select the filter in the list, make sure "Inbox" is selected at the bottom, and click "Run Now". This should delete all the bugspam. You can then delete the filter. Gerv