Known issues

This page contains a list of significant known issues that affect the experience of developing extensions for Firefox and Firefox for Android.

Content scripts don't appear in DevTools

Description: Content scripts sometimes don't appear in the sources list when debugging a tab on Android.

Workaround: Add a debugger statement to your content script to manually trigger a breakpoint when the content script first executes.

Tracking issue: Bug 1746718

Extension source don't update in DevTools

Description: Sources files open in DevTools are not updated after you edit the file on disk. This issue applies to temporary extensions installed in Firefox or on an Android device using web-ext.

Workaround: Close and re-open DevTools.

Tracking issue: Bug 1857368

"Destroyed actor" errors when debugging Android

Description: While debugging an extension on Android, you may encounter an error in Firefox on your desktop that says something like:

Cannot connect to the debug target. See error details below:

Error: Protocol error (Error): Attempted to write a response containing a destroyed actor from: root (resource://devtools/shared/protocol/types.js:358:17)

Workaround: In the about:debugging page on your development computer, disconnect from and reconnect to the Android device.

Additional notes: This issue appears to be related to simultaneous connections to the Android device from web-ext and Firefox's developer tools. To minimize the likelihood of this issue, set web-ext to auto-reload specific files only using the --watch-files flag. For example:

web-ext run -t firefox-android \
  --android-device=emulator-5554 \
  --firefox-apk=org.mozilla.fenix \
  --watch-file manifest.json

This approach also allows you to manually trigger a refresh by pressing R while the web-ext terminal window is focused.

Tracking issue: Bug 1856481