I guess I don’t fully understand which thread is which. After rereading, the forum post (https://forum.juce.com/t/calling-component-repaint-in-a-process-thread/9878) said never to call gui stuff from a process thread. I thought that was the main thread of the mainComponent above. I did not know it was a message thread (or even what a message thread is). I’ve got a lot to learn.