Sorry for the confusion here, it is a bit confusing if you’re not aware of the inner workings of SG Desktop.
The list you are seeing there determines what config to use for that project. So selecting a config in that list will mean that any of those actions/apps you run will run with that project config.
However, the key thing to know, is that SG Desktop when it starts, bootstraps the site config (based on the order I linked). This controls how Shotgun Desktop behaves when you have not selected a project.
When you select/enter a project in the SG Desktop UI, it is actually spawning off a separate python process and bootstrapping the project config, (which may well be the site config, if there isn’t a project specific config.) This spawned bootstrapped process, then communicates back to the main SG Desktop process in order to update the UI.
All of this is to say, that you can pick the project config via the UI as you have done, but that only affects project actions. You can’t pick the SG Desktop site level config like that, and the details you get in the about box come from the config that SG Desktop bootstrapped at a non project level. So you need to make sure that both configs have the correct tk-desktop engine.
I hope that makes sense?