Registering a new devtools panel causes infinite panels opened, only at firefox.

[ghost]

Bug Description
Registering a new devtools panel causes infinite panels opened, only at firefox.

Every time i click "panel" it opens another instance of "panel".

To Reproduce

• vue create extension
• vue add browser-extension
• at Which browser extension components do you wish to generate? mark Dev Tools Tab
• add this code to src/devtools/main.js:

chrome.devtools.panels.create('panel', '', 'devtools.html', function (panel) {
  console.log('hello from callback')
})

• npm run serve
• open firefox on macOS and load unpacked
• press F12

Expected behavior
As happens in chrome, a panel should only be added once.

Name	Version
vue-cli-plugin-browser-extension	0.24.0
Operating System	MacOS Mojave
Node	v13.12.0
NPM/Yarn	6.14.4
vue-cli	4.0.5
browser	Chrome, latest

[MCFreddie777]

I think this is correct behaviour. The devtools.html is added when the devtools are open and already contains dynamically injected script main.js. This script then creates new panel from devtools.html. Therefore you got into loop (dynamically loaded script creates new panel from itself).