Comment 2 for bug 599576

In 1.0.6, the "Assign" button is an <input type="submit"> style button.

In 1.2.0-rc1 the "Assign" button uses the new framework for adding buttons to forms so it's rendered as <button> tag - which then doesn't pick up the return key.

Given that you have to mouse up and down the list and mouse click each item you want to add, I'm not sure really why this is a massive problem - but I can see that being able to specify the button that gets pressed on return key might be useful elsewhere too, so perhaps look and see if that can get built in to the framework?