We again see the firefox problem that forms are not loaded completely in Mendix 4.4.4 and therefore buttons are visible in a form but clicking on them they will not function because of the class dijitInline mendixButton mendixButtonbutton mendixFormViewcontentButton mendixButtonbuttonDisabled See also this forum post with answer. I thought this bug was already squashed but it seems it is reintroduced again. Could somebody at Mendix verify that this was a bug and should not happen in Mendix 4.4.4?
try the following replace index(3).html to index-console.html and goto your application, open the console by pressing F12.
Check for too much recursion error message in the console. If so the fix isn't working and file a ticket.