partitioning - Why can't I Resize/Move in GParted?

I have a 12.04 LTS system running on my PC with a 320 GB hard drive.

Unfortunately, I need to use Windows 7 in my lab. I tried doing this using a virtual machine (VirtualBox and VMware) but it was not good enough. I want to make a partition on my hard drive so when the computer starts I'll choose between Windows 7 and 12.04.

I tried using Gparted, but for some reason I'm not getting the Resize/Move option.

There must be a way that I can do this without formatting and installing everything again.