Hi Mod – big troubles interacting with the drum riff and groove pages (and some aspects of the "Add notes" facility) using Mac 10.4.11 (with its default browser, Safari).
Basically, playback is intermittent. Also, when adding a drum riff, it never plays back on the drum riff page; it's only when you get to the groove page that you're able to hear it. "Delete" doesn't seem to work with regard to grooves on the "Account" page ... so my "Another (prelim)" seems to be chiselled in stone. (Hmmm – embarrassing – can you delete it please?)
If you need a guinea pig to test Mac functionality, happy to help as far as I can.
Otherwise enjoying the site! Glad you've KO'd the trolls!!