Browser monitors: window.dispatchEvent and window.addEventListener functions in application code

[nandini_balakri]

Summary

Chrome Manifest V3 (MV3), the latest iteration of the Chrome extension platform, introduces stricter execution and security constraints that can affect browser monitoring behavior.

One known consequence of MV3 is unexpected data loss or monitor failures when application code overrides core browser event APIs such as:

• window.dispatchEvent
• window.addEventListener

Problem

When core browser event API functions are overridden, Dynatrace Browser Monitors may exhibit the following issues:

• Missing resources or actions in waterfall data
• Missing or incomplete JavaScript event results
• Browser monitor execution failures

This behavior affects Browser Monitors run using older ActiveGates versions, <1.267.

How to Troubleshoot MV3‑Related Browser Monitor Issues

If you observe browser monitor anomalies that may be related to overridden event listeners, follow these steps:

1. Verify your ActiveGate version
   Ensure you are running ActiveGate version 1.267 or later.
   Earlier versions may not fully support Chrome MV3 behavior.
2. Update and retest your browser monitors
   After upgrading ActiveGate, rerun the affected monitors to confirm whether the issue is resolved.

What's Next

Contact Dynatrace Support if issues persist
If problems continue after upgrading, contact Dynatrace Support and provide a link to the monitor, along with details of the troubleshooting steps you have already completed.

Related Reading

📖  Update ActiveGate

📖  Browser Monitors

📖  Synthetic Troubleshooting Map