Emergency Workaround, tested for sidebar panel: <ctrl+z> restores the cut folder after unsuccessful 'paste' attempt; before <ctrl+z> you have to click into the bookmarks side panel, apparently at an arbitrary place.
ut paste folder: folder vanishes at original place when cut, but does not appear at target when paste Steps how to reproduce with Server-Installation of official en-US SeaMonkey 2.50a1 (NT 6.1; WOW64; rv:53.0) Gecko/20100101 Firefox/53.0 Build 20170110004313 (Default Classic Theme) on German WIN7 64bit: 1. Menu ‘Tools → Manage Profiles → [Create New Profile] → Create new Profile by assigning a name → [Finish] → Click newly created profile in list → [Use Profile] 2. In browser <f9> to open sidebar » In Bookmarks Panel you will find prepared Bookmarks folders 3. ‘Rightclick collapsed “Search the Web” folder → Cut’ » Folder will disappear 4. Click folder “SeaMonkey and mozilla” in “Bookmarks Menu” in Bookmarks Panel » expands folder 5. in “SeaMonkey and mozilla” on item “The SeaMonkey Project” ‘Rightlick → Paste’ » Expected: folder appears Actual: nothing happens, folder is lost a) Already REPRODUCIBLE with SeaMonkey 2.38a1 (Windows NT 6.1; WOW64; rv:41.0 nightly by Philip Chee) Gecko/20100101 Firefox/41.0 Build 20150620233542 (Classic Theme) on German WIN7 64bit b) was still ok with SM 2.37a2 (Win) Build 20150609235642 c) Works fine with FF 53.0a1 (2017-01-13) (32-bit) d) Menu 'Bookmarks → Manage bookmarks...' also affected e) You also can test with bookmarks of your normal profile, but be aware that you will loose bookmarks f) cut & paste of single bookmarks not affected
g) no obvious DUPs found with <https://bugzilla.mozilla.org/buglist.cgi?cmdtype=dorem&remaction=run&namedcmd=DUPs1331189&sharer_id=41036>
h) Also REPRODUCIBLE with English SeaMonkey 2.46a1 (X11; Linux x86_64; rv:49.0) Gecko/20100101 Firefox/49.0 Build 20160522003002 (Default Theme) on VirtualBox Ubuntu 14.04 LTS
CONFIRMED by user Andreas in unofficial German Blog: <https://seamonkeyde.wordpress.com/2017/01/14/bitte-um-datenverlust-bestaetigung-bei-cut-paste-von-bookmarks-ordnern-geht-der-ausgeschnittene-ordner-verloren/comment-page-1/#comment-428>
Kann ich auch bestätigen. Für den wollte ich schon seit Monaten einen Bug aufmachen :)
It's even worse, 'paste' will not add the folder at it's new place even for copy & paste.