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
setInput(newInput);
		}
		
		if (progressMonitor != null)
			progressMonitor.setCanceled(!success);
	}
	
	/*
	 * @see AbstractTextEditor#doSetInput(IEditorInput)
	 */
	protected void doSetInput(IEditorInput input) throws CoreException {
		super.doSetInput(input);
		configureTabConverter();
	}
	
	private void startBracketHighlighting() {
		if (fBracketPainter == null) {
			ISourceViewer sourceViewer= getSourceViewer();
			fBracketPainter= new BracketPainter(sourceViewer);
			fBracketPainter.setHighlightColor(getColor(MATCHING_BRACKETS_COLOR));
			fPaintManager.addPainter(fBracketPainter);
		}
	}
	
	private void stopBracketHighlighting() {
		if (fBracketPainter != null) {
			fPaintManager.removePainter(fBracketPainter);
			fBracketPainter.deactivate(true);
			fBracketPainter.dispose();
			fBracketPainter= null;