UserAgent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/72.0.3580.0 Safari/537.36

Steps to reproduce the problem:
1. Put bg.js, inject.js, manifest.json in a directory
2. Load an Unpacked extension from chrome://extensions
3. Put test.html in a directory and start an HTTP server there (for example on port 8080)
4. Visit http://127.0.0.1:8080/test.html

What is the expected behavior?
On the dev tools console the line INJECT should appear only once

What went wrong?
The line INJECT appear twice

Did this work before? No 

Does this work in other browsers? N/A

Chrome version: 72.0.3580.0  Channel: n/a
OS Version: 
Flash Version: 

It is my understanding that an injected script should be executed only once in a given page. This test case shows that if another, independent, rule matches in page the injection happens twice.

In this case if there is a <p> element a SetIcon action is triggered. If there is no <p> in the page the SetIcon action does not trigger and the script is injected only once.
 

Deleted: bg.js 599 bytes

bg.js 599 bytes View Download

Deleted: inject.js 23 bytes

inject.js 23 bytes View Download

Deleted: manifest.json 240 bytes

manifest.json 240 bytes View Download

Deleted: test.html 146 bytes

test.html 146 bytes View Download