Thank for the useful explanation - and the workrounds.

I agree that the new method provides considerable improvement of work flow.  However, increased eye strain due to the poorer rendering of the text within a web page is a considerable disadvantage.  Having just had my previous Moodle provider withdraw services with little chance of grabbing the archive, I am even more reluctant to put all my archive eggs in a provider's basket.  The method also relies on having good consistent internet connection. I frequently mark on trains, in cafes and other places with iffy connections where intermittent loss or reduction of connection would make make life even more difficult than it is at present.

From my point of view, a method of marking locally, but within the Moodle management structure (? a thick client), would be the best solution.