It's a known cosmetic issue on newer versions of macOS with Isadora 4.1.3 and older.

This is fixed already for the release that's coming very soon.

In the meantime, you'll see that those areas are only blank when you do not have MIDI, OSC, Serial, or TCP/IP data going to or from Isadora. As soon as data is going in or out, the relevant section of the UI will update.

In its simplest form, you can do this to see what I mean:

Here's a slightly more complex example that demonstrates the same thing, but cycles through each of those four data types: DOWNLOAD

(NOTE: The MIDI won't work unless you use the settings shown in the screenshot for Communications > MIDI Setup > Port 1 > (Input and Output set to "Isadora Virtual Out")