User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.0; de; rv:1.9.0.7) Gecko/2009021910 Firefox/3.0.7 Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 6.0; de; rv:1.9.0.7) Gecko/2009021910 Firefox/3.0.7 When deleting less than 10 entries from the history sidebar at once, nsINavHistoryObserver:onDeleteURI() fires for every entry. But when deleting more than 10 entries from the sidebar at once, onDeleteURI() doesn't fire at all, only onBeginUpdateBatch() fires. Reproducible: Always

that's expected, when we remove more than 10 entries we do batch, so single observer calls are skipped.

And how can I find out when more than 10 pages are deleted at once, and which ones they are?

no way, atm, you only know something has changed

no reasons to stay UNCO, we should still notify things even in batch mode, is the observer that should ignore those notifications if it does not need them

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

fixed with bug 630240