Bug 52346 [misc] Undo yields wrong code
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/javaeditor/CompilationUnitEditor.java
void customizeDocumentCommand(IDocument document, DocumentCommand command);
	}
	
	class AdaptedSourceViewer extends JavaSourceViewer  {
				
		private List fTextConverters;
		private boolean fIgnoreTextConverters= false;
		private JavaCorrectionAssistant fCorrectionAssistant;
		
		public AdaptedSourceViewer(Composite parent, IVerticalRuler verticalRuler, IOverviewRuler overviewRuler, boolean showAnnotationsOverview, int styles) {
			super(parent, verticalRuler, overviewRuler, showAnnotationsOverview, styles);
		}
				
		public IContentAssistant getContentAssistant() {
			return fContentAssistant;
		}
		
		/*
		 * @see ITextOperationTarget#doOperation(int)
		 */
		public void doOperation(int operation) {
		
			if (getTextWidget() == null)
				return;
			
			switch (operation) {
				case CONTENTASSIST_PROPOSALS:
					String msg= fContentAssistant.showPossibleCompletions();
					setStatusLineErrorMessage(msg);
					return;