public void updateProjectionStackStatus(boolean haveBackProjections,boolean haveForwardProjections){
  forwardProjectionButton.setIcon(haveForwardProjections ? forwardIcon : forwardDimIcon);
  backProjectionButton.setIcon(haveBackProjections ? backIcon : backDimIcon);
  forwardProjectionButton.setEnabled(haveForwardProjections);
  backProjectionButton.setEnabled(haveBackProjections);
}

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