Visualizer not working on MacOS

My first attempt at using gSender 1.0.2 on MacOS Catalina 10.15.7.

I am able to connect to the machine just fine. Homing and probing work no problem. However, after loading a gcode file I don’t get anything in the visualization window except a “sad” icon. I tried several different gcode files all generated from Carbide Create.

Is this environment supported? (It’s and older Mac, so I can’t update the OS to anything newer.)

UPDATE: After quitting and restarting gSender, the Visualizer started working.

As another data point, gSender is working fine for me on a 4GB 2008 iMac with OSX 10.11 (I did have to connect via an external hub to make it reliable, this seems to be an issue with 10.11 and Arduinos)