Bugzilla

## What were you doing?

1. Open DevTools Debugger
2. Check Disable JavaScript
3. Close DevTools

## What happened?

JS doesn't work in any tab.

## What should have happened?

Disabling JS only affects the current tab and is reset when DevTools closes, similar to Disable Cache.

## Anything else we should know? 

This can be a massive footgun for developers. Regression as the option is much easier to find now and can surprise more developers.

## What were you doing?

1. Open DevTools Debugger
2. Check Disable JavaScript
3. Close DevTools

## What happened?

JS doesn't work in any tab.

## What should have happened?

Disabling JS only affects the current tab and is reset when DevTools closes, similar to Disable Cache.

## Anything else we should know? 

This can be a massive footgun for developers. I marked this regression as the option is much easier to find now and can surprise more developers.

The root cause is that the new Debugger settings menu does toggle the global `javascript.enabled` setting. The existing *Disable JavaScript* in *Settings* [sets](https://searchfox.org/mozilla-central/rev/fc91a093e40dde71d10ad219946b8ae775aca9eb/devtools/server/actors/targets/browsing-context.js#1155) a [docShell specific flag](https://searchfox.org/mozilla-central/rev/fc91a093e40dde71d10ad219946b8ae775aca9eb/devtools/server/actors/targets/browsing-context.js#1237) which gets reset when DevTools closes (and also handles refresh on toggle).

## What were you doing?

1. Open DevTools on *Debugger*
2. Check *Disable JavaScript* in the settings menu.
3. Close DevTools

## What happened?

JS doesn't work in any tab. Debugger has to be opened again and the option unchecked.

## What should have happened?

Disabling JS only affects the current tab and is reset when DevTools closes, similar to Disable Cache.

## Anything else we should know? 

This can be a massive footgun for developers. I marked this regression as the option is much easier to find now and can surprise more developers.

The root cause is that the new Debugger settings menu does toggle the global `javascript.enabled` setting. The existing *Disable JavaScript* in *Settings* [sets](https://searchfox.org/mozilla-central/rev/fc91a093e40dde71d10ad219946b8ae775aca9eb/devtools/server/actors/targets/browsing-context.js#1155) a [docShell specific flag](https://searchfox.org/mozilla-central/rev/fc91a093e40dde71d10ad219946b8ae775aca9eb/devtools/server/actors/targets/browsing-context.js#1237) which gets reset when DevTools closes (and also handles refresh on toggle).