fix regression in zooming

caused by b55c765c0450607df21ff4e377544e42b427896b

the bug could be seen as follows: open Fire (or any model really);
zoom two steps larger; __reload; zoom two steps smaller; the font
size is now a little larger than it should be, as you'll see if
you do __reload again and the font snaps back to the right size

I think the old logic in storeComponentFont was actually wrong, and
before b55c765, conditions weren't right for the bug to show up, but
now they are