Bug 65268 [projection] editor is missing collapse all action for code folding
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/actions/FoldingActionGroup.java
public void update() {
			setEnabled(FoldingActionGroup.this.isEnabled() && fViewer.isProjectionMode());
		}
		
	}
	
	private ProjectionViewer fViewer;
	
	private final PreferenceAction fToggle;
	private final TextOperationAction fExpand;
	private final TextOperationAction fCollapse;
	private final TextOperationAction fExpandAll;
	private final PreferenceAction fRestoreDefaults;
	private final FoldingAction fCollapseMembers;
	private final FoldingAction fCollapseComments;
	
	private final IProjectionListener fProjectionListener;
	
	/**
	 * Creates a new projection action group for <code>editor</code>. If the
	 * supplied viewer is not an instance of <code>ProjectionViewer</code>, the
	 * action group is disabled.
	 * 
	 * @param editor the text editor to operate on
	 * @param viewer the viewer of the editor
	 */
	public FoldingActionGroup(final ITextEditor editor, ITextViewer viewer) {
		if (!(viewer instanceof ProjectionViewer)) {
			fToggle= null;
			fExpand= null;