Hi there wickedtall person! Sorry about how late this reply is... did you ever figure it out? I have a couple of resources that might help you out if you're still facing this issue. First of all, it's my understanding that topcoat is depreciated. You might want to try out spectrum-css, which was very recently open sourced. Here are the docs. Also check out this article on Spectrum by DBarranca As for quitting and restarting Photoshop to test the changes, that is, indeed, a slow and frustrating process. I wound up creating the following image in order to remember how it worked for this article: Turns out this is true for Photoshop, but in After Effects and Premiere Pro you only need to close and open your panel. Right now you're using CEP to build a Photoshop panel, but soon we how to bring UXP to Photoshop, which will, eventually, make the panel/extension development process much faster, with far fewer app restarts and easier-to-use UI elements. I know none of this directly answers your question but I hope it's somewhat helpful. Let me know! - Erin
... View more