Thanks so much to both of you for replying so quickly, James and Tom! I've had such a great time using both of your tools.
Tom, I really appreciate you jumping on this right away -- using alternative keys would work perfectly for this. I tried the alternative image but unfortunately I'm getting a checksum error -- I could probably fix this myself, but I'm not familiar enough with the image format to make a guess where the checksum is located in the file.
James -- it would be awesome to have a key combination available for the arrow keys, if it's not too much trouble. The Selector is so far the only piece of software that I've had an issue with, so if we're able to resolve it with an updated image it wouldn't be critical to have the function.