Two things. During ascent the g load on the passengers is steadily increasing. By the time you're 6:30 into the burn, you'll be experiencing about 2.5g, and just before MECO at about 8:15 into the burn you're close to 3.2g. I'm not sure using a touch screen in a high-g environment is a good idea.
Second thing, right after MECO you're suddenly very close to 0-g. Which is a fun ride to be sure, but _everything else_ in the cabin is suddenly weightless as well. Items have a tendancy to start floating around the cabin and knocking into things.
> There's not that much for the astronauts to do in Dragon though, so it's probably all OK.
When everything is going according to plan.. there isn't much to do. This isn't the scope you want to design for, though.