As already mentioned in Unofficial SeaMonkey 2.53 by user wg9s and Test Results for Add-Ons from ca-archive, “Go Parent Folder” (and also “Show Parent Folder”) don’t work any longer with latest 2.53 by user wg9s
- “Go Parent Folder” context menu appearing after rightclick on a bookmarks entry does no longer show the Item “Go Parent Folder”, Problem is visible in Bookmarks Manager and in Sidebar Bookmarks Panel.
- “Show Parent Folder”: Table column can no longer be added in Bookmars Manager.
Go Parent Folder and Show Parent Folder both worked in Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:56.0) Gecko/20100101 Firefox/56.0 SeaMonkey/2.53a1 Build 20170731233559. That was a version with the little column selector in the most right table heading in Bookmarks Manager.
The first version still available on my PC where both addons do no longer work is Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:56.0) Gecko/20100101 Firefox/56.0 SeaMonkey/2.53 Build 20180902143701. And in this version also the little column selector in the most right table heading has gone. That proves nothing, but might indicate the reason why the addons do no lnger work.