Tabbing issue with populating the invoice ref field

When entering an invoice item, after selecting the client & project, Freeagent has a think [1] then populates the invoice ref with a proposed value. Unfortunately (in Safari at least) if you have this field selected because you've tabbed to it (I tend to tab through forms as I find it quicker), the focus is lost after it's populated with the proposed value. I suggest the following slightly trickier possibility:

* FA gets the proposed ref
* FA checks to see if the invoice ref field it selected
* If the field is selected, populate the field as it does currently, then (if poss) reselect the field and the entire value in it so the user can either change it or simply tab onwards

Maybe even an on page spinner to show that FA is thinking?

[1] Contacts the server to request a proposed invoice ref via AJAX, I assume.