Well, both iframes scroll nicely on my PC and Android phone. They both scroll on my wife's new Ipad. But on my old beast of an Ipad, the left hand box is tall enough that scrolling isn't necessary. The right hand box (spreadsheet) scrolls OK. I can't try her phone until she gets home from work.
I saw RKissane's entry and tried zooming the left hand box, but that had no effect. It was still a tall box with all text showing and hence, didn't need scrolling. Weird.