I'm developing a theme using a test installation (using InstantWP), but when I upload it to a staging site, for some reason the nav menu looks inflated. After looking at the source, it turned out to be that for some reason my test install uses the class
.sub-menu while the staging install uses
Both installs are fresh installs of 3.3.1 with the exact same plugins installed. Why would there be such a discrepancy between the two installs?