size...
I have a 13" macbook pro, and while the table fits well on the screen, the info window does not. It is a little too long and the isotopes section is hidden (goes behind the dock and off the screen). If it could scroll up and down, it would me MUCH more useful.
Otherwise it is a great app; I highly recommend it. I even find myself going into it just to read about elements (for fun) :)
d.zuul about
iElements Periodic Table, v1.4