jalview hangs and becomes unusable when mouse hovering over sequence with structure shown in chimera and horizontal scrolling with trackpad

Particularly noticed with chimera but may impact in Jmol too.

With a mouse hovering over a sequence with structure, the mouse over highlighting in chimera blocks Jalview's GUI thread. Scrolling on a trackpad horizontally fires label update events rapidly, these all queue up and get actioned in chimera before Jalview's MSA view updates to the last scrolled to position, making it impossible to scroll precisely.