> Another thing:
>
> If you enable the flaps, you can see that they can not be resized as before
> (for example in 4.5) by dragging their handle: instead, they simply close.

Confirmed.  And some of the flaps don't open far enough to access all
the tools so they're basically inaccessible.

It also looks like the FlapTabs look more like beveled rectangles than
the classic flap-tab.

If anyone knows a fast fix over the weekend, the release will be grateful.