New Article - change unread timeout

[bin]

Hi

In most email clients you can change the time that an email will show as unread when you are looking at it.

In OTRS Agent I'd like to be able to extend the amount of time that the yellow star stays yellow so that the article can be quickly scanned and still keep the yellow star. It seems to change after a couple of seconds at the moment.
I've looked in various places but not been able to find a setting - presumably one of teh pm files - searched for unread, seen, etc but no luck.

Any advice most welcome

bin