Bug 88309 Reenable sort members on enums
org.eclipse.jdt.ui/ui/org/eclipse/jdt/ui/actions/SortMembersAction.java
private boolean checkEnabledEditor() {
		return fEditor != null && SelectionConverter.canOperateOn(fEditor);
	}	
	
	
	
	/* (non-Javadoc)
	 * Method declared on SelectionDispatchAction
	 */
	public void selectionChanged(IStructuredSelection selection) {
		boolean enabled= false;
		enabled= getSelectedCompilationUnit(selection) != null;
		setEnabled(enabled);
	}	
	
	/* (non-Javadoc)
	 * Method declared on SelectionDispatchAction
	 */
	public void run(IStructuredSelection selection) {
		Shell shell= getShell();
		try {
			ICompilationUnit cu= getSelectedCompilationUnit(selection);
			int cuMembers= cu.getTypes().length;
			
			IType type= cu.findPrimaryType();
			int memberCount= type.getChildren().length;
			if (cuMembers <= 1 && memberCount <= 1) {
				MessageDialog.openInformation(getShell(), getDialogTitle(), ActionMessages.getString("SortMembersAction.no_members")); 			
				return;