Why can't I Resize/Move in GParted?

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http://askubuntu.com – 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. (HowTos)