Cloned from https://bugzilla.redhat.com/show_bug.cgi?id=1186863
Description of problem:

When creating a new compute profile for a libvirt instance, the Storage section for the Allocation text box does not change when depressing the Full button. The compute profile must first be saved and then reopened for editing. Then the Full button must be depressed again for the value to change from 0G to a positive value. This also can be unreliable. There are combination of depressing the button that can get the value out of sync and go back to 0G and then get stuck at 0G again until you save and reopen for editing.

See screenshot attached.