Bug 28698 Ctrl+O (show outline) does not work if the file being shown in the editor is read only
M4 The summary tells all. Works if the file is not read only. Is this by design?
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/javaeditor/CompilationUnitEditor.java
return;
		}
		
		if (selection.getLength() < 0)
			targetOffset -= selection.getLength();
			
		sourceViewer.setSelectedRange(targetOffset, selection.getLength());
		sourceViewer.revealRange(targetOffset, selection.getLength());
	}
	
	/**
	 * Ses the given message as error message to this editor's status line.
	 * @param msg message to be set
	 */
	protected void setStatusLineErrorMessage(String msg) {
		IEditorStatusLine statusLine= (IEditorStatusLine) getAdapter(IEditorStatusLine.class);
		if (statusLine != null)
			statusLine.setMessage(true, msg, null);	
	}
	
	private IProblemAnnotation getNextError(int offset, boolean forward, Position errorPosition) {
		
		IProblemAnnotation nextError= null;
		Position nextErrorPosition= null;
		
		IDocument document= getDocumentProvider().getDocument(getEditorInput());
		int endOfDocument= document.getLength(); 
		int distance= 0;
		
		IAnnotationModel model= getDocumentProvider().getAnnotationModel(getEditorInput());