Bug 17423 Revert apears twice in the popup menu.
Build F1. 1) Open a java editor. 2) Popup the menu. There is only one Revert option disable as it should be. 3) Make the editor dirty. 4) Popup the menu. There are two Revert option in the menu. One after UNDO and other before FORMAT.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/javaeditor/CompilationUnitEditor.java
public void addTextConverter(ITextConverter textConverter) {
			if (fTextConverters == null) {
				fTextConverters= new ArrayList(1);
				fTextConverters.add(textConverter);
			} else if (!fTextConverters.contains(textConverter))
				fTextConverters.add(textConverter);
		}
		
		public void removeTextConverter(ITextConverter textConverter) {
			if (fTextConverters != null) {
				fTextConverters.remove(textConverter);
				if (fTextConverters.size() == 0)
					fTextConverters= null;
			}
		}
		
		/*
		 * @see TextViewer#customizeDocumentCommand(DocumentCommand)
		 */
		protected void customizeDocumentCommand(DocumentCommand command) {
			super.customizeDocumentCommand(command);
			if (fTextConverters != null) {
				for (Iterator e = fTextConverters.iterator(); e.hasNext();)
					((ITextConverter) e.next()).customizeDocumentCommand(getDocument(), command);
			}
		}
		
		public IVerticalRuler getVerticalRuler() {
			return fCachedVerticalRuler;
		}