P20 locks up

Doing P20 trial, most everything I tried is working OK, but found a bug, consistent every time:

If I try to move an icon in a custom panel (shift+drag), P20 immediately locks up (in a 11% CPU loop in win10 task manager) and cursor sticks at selection icon with ghost of paintbrush showing too. Cursor moves OK with mouse or Wacom pen; just won't accept a mouse click.

Nothing works in P20, can only close via task manager "end task". Mouse works OK for everything not P20.

My PC spec give all green for performance of P20.

Start P20 and it is OK, setup to last saved workspace and works normal (except for custom panel icon move).

Anyone have a solution? or something to try for a fix?