question: public void updateProjectionStackStatus ( boolean haveBackProjections , boolean haveForwardProjections ) { forwardProjectionButton . setIcon ( haveForwardProjections ? forwardIcon : forwardDimIcon ) ; backProjectionButton . setIcon ( haveBackProjections ? backIcon : backDimIcon ) ; forwardProjectionButton . setEnabled ( haveForwardProjections ) ; backProjectionButton . setEnabled ( haveBackProjections ) ; }
target:  Respond to changes in the contents of the forward and back projection stacks.