I agree with … well… pretty much everyone. On everything.
Rhino toolbars were not perfect before, but now pretty much everything is worse!
On one side it seems somewhere someone tried to make things better, but the outcome is the opposite.
Everything seems more abstract and “ephemeral” , inaccessible.
This is one of the reasons because is difficult to try/test Rhino Wip/Beta in everyday work.
Why opening the “Show toolbars…” takes many seconds to open? (Not only the first time. Every time!)
My pc specs are good enough to expect a 1ms delay for this kind of “tasks”!! (like in rhino 7?) … and yet, this “complex operation” takes the same time on 2011 hardware! Is the list on the cloud?
Here juggling with the cursor while waiting. Rhino UI completely frozen until it opens…
What is that Libraries “default” …?
Why it glitch open at a different size and then it quickly rearrange to a shorter scrollable list?
This last point^ is very frequent on almost everything of the new UI: windows do pop at some random size and style and then it get fixed to the chosen final design.
This resize twice after simply moving it (slowed down the second time):
(and container still don’t remember sizes…)
All this “hiccups” on the UI make Rhino feels less modern than Rhino 7.
Actually less modern than Rhino 4. imo.
Please don’t ““fix”” things this way.
This is duct tape to fix a bridge.
Build a better bridge and use no duct tape at all. Please 
(making the resize still happening but hidden, is using duct tape again, in case someone wondered)