MS4, "Pallets, Instruments, Properties" not resizeable

I've noticed that in MS4, unlike in MS3, panels on the left (Pallets, Instruments, Properties), are not resizable.
I guess that's a bug?

Btw, they also behave quite strange when I undock them and then try to return them back in the same position they were before - docked one next to the other, with one overlaying other two.
I can't really explain, it would take recording a video, but they behave unlike any other panels I've ever used in any software. When I try to position one above other, hoping that they will dock together, it just doesn't happen.

So it probably has to be bug.

Windows 10.