The browser action icon flickers when the worker reloads

[fregante]

Describe the bug

I'm not sure if it's worth dealing with this, but I thought I'd document it.

Actual behavior

Notice the icon switch to gray for a moment. This is due to the aptly-named grayIconWhileLoading

Expected behavior

grayIconWhileLoading should not run after the first load

To Reproduce

1. Have a browser window open long enough for the worker to be deactivated
2. Open a new tab

or:

1. Close all windows
2. Wait a bit
3. Open a new window

Additional context

I think grayIconWhileLoading is super useful while developing and actually this "bug" can help us see when the worker has been reloaded.

Solutions

• Once available, we could use runtime.onEnabled to only run that script once
• I actually have a listener for this, but I'm not 100% confident it works: https://github.com/fregante/webext-events/blob/main/source/on-extension-start.md