Structure menu "View | Colour By..." changes alignment colouring

Make two views of uniref50 with different colouring and show a sequence structure.
Use the "View | Colour by..." menu to switch view used for structure colour.
ok.
Use it again to switch back to the first view.
The colours of the second view get set on the first alignment view.
In fact, this happens on mouse into the menu option for the view (no select of the option needed).