[Interest] Items vanish from grid when i move down?

[Mark]

Hi,

I'm playing with a GridView and animations. What i want to have is
animate the items _only_ when i resize my window (thus the grid gets
smaller/bigger). The following snippet does that "somewhat".  Somewhat
because it animates always, also when added and scrolling..

Now the actual issue is this. When i scroll down the items vanish from
my grid! Why does that happen and how should i fix that?

Any suggestions on fixing the animation to only work when the window
is resized would also be welcome.

The snippet: http://paste.kde.org/606980/

Cheers,
Mark