Change application's starting activity

Question

I have created the meat and guts of my application but I want to add a different activity that will be the starting point (sort of a log-in screen).

Couple questions

Answer 1

In a recent project I changed the default activity in AndroidManifest.xml with:

In Android Studio 3.6; this seems to broken. I've used this technique in example applications, but when I use it in this real-world application it falls flat. The IDE once again reports:

Error running app: Default activity not found.

The IDE still showed a configuration error in the "run app" space in the toolbar (yellow arrow in this screenshot)

To correct this error I've tried several rebuilds of the project, and finally File >> "Invalidate Cache/Restart". This did not help. To run the application I had to "Edit Configurations" and point at the specific activity instead of the default activity: