"The people most likely to be able to provide you with a solution are Mozilla Support " - that is pretty obvious, and so I am liklely to have done it without getting a response, but I will follow that up.
I have now asked the Firefox Forum, but - I've received no reply - a work in progress.
I will approach the mozillaZINE forums.
I got the suggestion to try a portable Firefox - and clicking on its 'Show all Bookmarks' also creates another icon in the TaskBar, but it behaves the way I expect Firefox to behave. So I have a work-around without solving the mystery.
I still had a clone of the system made in December when Firefox still worked, and I have a record of all the changes I made since then, so I am starting over with that clone and re-doing all the changes - and will monitor whether Firefox Bookmarks Manager stays functional. Will keep cloning so I always have a version of the system BEFORE it got damaged. I'll let you know if I discover the culprit that damaged Firefox.
I can not yet satisfy your curiosity about the cause of my problem; but I can tell you that I have spent hours on repeating the various tweaks I did on the system since December. I've not yet attempted the most risky procedure of re-installing new software and updating 'old' software, but I will get round to that. I frequently check that the Firefox Bookmarks Manager is still functional, and certainly it is no longer a blank icon. However it is not FULLY functional to the extent that when I set VIEW to 'sorted' & 'from A to Z', it does not have effect; and when I check the setting again, it is UNSORTED which is ticked.
I have pretty, much restored my system with all updates and tweaks to where it was when I found Firefox Bookmarks Manager disabled, yet Library still opens the way it should, so I think you hope in vain for an explanation to know the cause of my troubles. Thank you for your valient but vain attempts at tracking down the culprit.
A forum community dedicated to tech experts and enthusiasts. Come join the discussion about articles, computer security, Mac, Microsoft, Linux, hardware, networking, gaming, reviews, accessories, and more!