Retain preview URL within the Activity QA screen

Currently, within the Activity QA screen it is possible to enter the URL of the page you want to preview (to build the full QA link).   It would be useful if what was inputted was retained.

At the moment it seems the URL is discarded as soon as you navigate away from the underlying page.  The impact is that you have to keep looking up what URL the activity is meant to be running on in order to preview it which is a bit of a pain!

Given the frequency with which this is accessed it would be greatly appreciated if you could fix this