It's been some time since I've had a chance to use the ModelBuilder tool in Toolbox.
I had to upgrade an outdated data import routine and figured it would be the best way to do it. When I right-clicked my newly created tool, I tabbed through the options and got to the Iteration tab ... then as my eyes gazed down the interface, I saw this (screenshot attached) and had to do a double-take.
I use version 10.0 where I work - hopefully someone caught this and discreetly fixed it via a service patch, but if not, maybe someone should.
It's been some time since I've had a chance to use the ModelBuilder tool in Toolbox.
Just thought I'd add -- I highly recommend you look into using the 10.x iterator tools. IMHO the new iterator tools are much easier to work with than the older 9.x iterating method shown in your screen shot.