Android studio instant run disabled

Question

When I start my application in Android Studio (Gradle 2.3.3, buildToolsVersion 26.0.1, compileSdkVersion 26, debug variant), the Instant Run button appears disabled constantly. If I hover on it, it says "Apply changes: No active XXX launch", even though it's currently running on the emulator. Any idea why?

May be related: the Stop Process button shows a small "2" on it, and there are two options for stopping processes: XXX, and XXX-java (query XXX is the name of the main module)

Answer 1

My suspicion was correct. When running, instead of debugging, there's only one process started, and THEN the Instant Run works. So, the question now becomes WHY does debug launch 2 processes.

However, I understand this is a different question, so I'm closing this one and making a new one, for the sake of clarity.

Here's the link