Question / Help Game Capture (Syphon): Source: Nothing to select in the box

[David Needham]

Here's my log: https://gist.github.com/df4fee393bba2e5445ef99f2345e647f

I'm new to OBS and trying to record gameplay locally.

1. I installed OBS Studio, SyphonInject, and SoundFlower and restarted the computer.
2. I started OBS and added "Game Capture (Syphon)" as a source.
3. In the properties for this source, I see a selectbox for "Source", but there's nothing inside.
4. If I click the "Launch SyphonInject" button the app opens, but none of the buttons actually seem to do anything.
5. I can check the "Inject" option and select an app, but nothing seems to change in the preview.
6. I click "Start recording", switch to the app, click around, and click back to "Stop recording".
7. The video created is blank (black screen).

Any ideas? I'm sure that I'm doing something obvious wrong, but I don't see any other posts that mention this particular problem.