Hi Josh, thanks for finding time to post this info on our forum. Indeed, this is a limitation of the version of the MONO framework that we're using currently with our SpotEditor on MAC OSx in that it doesn't let us show right click menu via X11 user interface or use mouse events in the same way we do this on Windows for the arrow keys. We're reworking our MAC UI to be native so this limitation will go away soon.
Pushing to get it out within two or three months. There's a lot of new features in the new SpotEditor (image editing, cropping, resizing, watermarking, color balance, sharpness, levels, brightness, contrast, FTP / cloud uploaded and more).