Simplest practical solution to bouncing progressbar morphs. If there are any active slots we ignore requests to change the 'requestedPosition'.
=============== Diff against Morphic-mt.1615 ===============
Item was changed:
----- Method: SystemProgressMorph>>requestedPosition: (in category 'accessing') -----
+ "only change the progress bar position if this is an occasion when the progress bar is opening with a single active bar. After that we don't want to change the position and leap around the screen"
+ activeSlots < 1 ifTrue:[ requestedPosition := anObject]!
- requestedPosition := anObject!