Oops, spoke too soon. Toolbar malfunction still there , but bypassed by showing "News and interests" , then dismiss.
Seems to be fixed - MS Update KB5003637 did the trick? All OK.
OK, but when push comes to shove, I suspect MS is going to be the "winner".
Sorry, but I feel it really is a Stardock issue, if they wish to remain relevant in this field of Windows utilities/embellishments - as long as Microsoft continues to change and develop the operating system, for better or worse. I am glad to have moved on from DOS on umpteen floppies. I am also glad (and grateful) to have enjoyed using Fences for however many years, but ........
I endorse comments of rs426. "As for it being a Microsoft issue....Microsoft, like other software is constantly evolving with new features and changes to old. Seems to me, that when MS pushes a change, it is up to companies like Stardock to adapt. MS is not going to remain static! " It is hardly fair to expect Microsoft to cater for all the software utilities users adopt over the years. It would seem fair that companies like Stardock adapt their software to suit,
21H1 update, sorry.
I note that Fences incompatability, since 20H1 Windows update, seems to occur only with laptops, or with less common screen definitions. My Asus desktop, displaying on a 1920 x 1080 monitor, is still working OK with Fences. My laptop is a Huawei displaying 3000x 2000, and 250% on screen scaling. I've gone back to Windows Start Page and taskbar is working again, with Fences 3 uninstalled.
Exactly same issue as jimryan2- have disabled Fences and Problem disappeared (Huawei Matebook X Pro) The task bar icons started to flicker and disappear (right side only in notification area - exactly as reported above). At this stage my laptop is working fine without Fences - but I will wait till this bug is fixed before I reinstall it .