I see a few other similar posts - but want to add my experience here too to help the developers, as well as users of GF that may be having the same issue.
First the stats: I'm running WordPress 3.5.1, on a PC (Win7). The issue occurred in both Chrome (current: 26.0.1410.64) and Firefox (20.0.1). I did not try it in other browsers.
I have been working in GF extensively for a week. This morning I upgraded to 1.7.2, and immediately after upgrading, I was no longer able to edit my form fields. I can go into Forms, select my form, and reach the edit form field (can also see form settings, notifications, etc.) -- but when I attempt to edit any of the fields nothing happens. Typically when I would hover over the form field it would highlight and then I could see the Edit and other buttons, but this stopped happening. I tried to click the fields - nothing happened. Also, the sidebars with "standard fields" "advanced fields" etc - would not work. Meaning, I click, nothing happened. Could not collapse those boxes, either (they defaulted to all being open).
I went into GF settings and turned on no-conflict, and everything started to work again, which is great, but it seems to me there is a big problem somewhere if that was necessary to do, so I wanted to let you know.