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
String defaultEncoding= storageProvider.getDefaultEncoding();
			if (encoding != null && !encoding.equals(defaultEncoding)) {
				Shell shell= getSite().getShell();
				String title= JavaEditorMessages.getString("CompilationUnitEditor.warning.save.nonWorkbenchEncoding.title"); 
				String msg;
				if (input != null)
					msg= MessageFormat.format(JavaEditorMessages.getString("CompilationUnitEditor.warning.save.nonWorkbenchEncoding.message1"), new String[] {input.getName(), encoding});
				else
					msg= MessageFormat.format(JavaEditorMessages.getString("CompilationUnitEditor.warning.save.nonWorkbenchEncoding.message2"), new String[] {encoding});
				return MessageDialog.openQuestion(shell, title, msg);
			}
		}
		return true;
	}
	
	/**
	 * Jumps to the error next according to the given direction.
	 */
	public void gotoError(boolean forward) {
		
		ISelectionProvider provider= getSelectionProvider();
		
		ITextSelection s= (ITextSelection) provider.getSelection();
		Position errorPosition= new Position(0, 0);
		IProblemAnnotation nextError= getNextError(s.getOffset(), forward, errorPosition);
		
		if (nextError != null) {
			
			IMarker marker= null;
			if (nextError instanceof MarkerAnnotation)