Without the possibility to take a closer look at this situation, it's hard to say why all the different options are grayed out. However, the reason you cannot edit the virtual disk size could either be related to the virtual disk controller being an IDE controller or - in most cases - because the VM has an active snapshot. If the virtual disk's file name in the VM's properties contains s.th. like "...-00000x.vmdk" then you need to delete the snapshot(s) using the Snapshot Manager before you can increase the disk size.
André