STR: 1. Start firefox with new profile 2. Show sidebars, expand 'Bookmarks Menu' tree 3. Show all bookmarks(Library window) 4. Backup bookmarks 5. Restore with that file AR: Bookmarks tree items are doubling.(in this case) ER: No any changes. Another STR: 1. Show sidebars, expand 'Bookmarks Menu' tree 2. Add a new bookmark folder 3. Show all bookmarks(Library window) 4. Restore with backed up file AR: Added folder stays there. ER: Added folder vanished, fully replaced with backed up bookmarks. mozregression: 10:02.26 INFO: Last good revision: e72d0fc07a0bb274bd525f65c14bfc5ea7eae9f8 10:02.26 INFO: First bad revision: 409b4345b85aba3bd93b83c6f9a6a194a2d5073a 10:02.26 INFO: Pushlog: https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=e72d0fc07a0bb274bd525f65c14bfc5ea7eae9f8&tochange=409b4345b85aba3bd93b83c6f9a6a194a2d5073a This is temporary problem of the treeview. Switching sidebar(->History->Bookmarks) or reopening sidebar solves the issue.
Thanks for the report, I can confirm the regression.
I've just had bug 1371679 backed out, I'll address this when it lands, but this is "fixed" for now.