# Known issues specific to MV3 extensions

> The Click activity with the `Simulate` input method no longer works on HTML elements that have a click handler with `javascript:` URI.

## Click activity with Simulate fails on specific web page elements

The Click activity with the `Simulate` input method no longer works on HTML elements that have a click handler with `javascript:` URI.

![docs image](https://dev-assets.cms.uipath.com/assets/images/studio/standalone-docs-image-168089-fe7781dd.webp)

In this case, the simulated click will not take effect and no errors will be reported.

This was reported as a [Chromium bug](https://bugs.chromium.org/p/chromium/issues/detail?id=1299742). This issue is quite rare as very few HTML elements have click handlers in this form.

### **Workarounds**

Two workarounds are available for this issue:

1. Identify the failing **Click** activity in your workflow and change the input method from **Simulate** to any other input method (Chromium API, Hardware Events, Window Messages).
2. Upgrade to **UiPath.UIAutomation.Activities** package **v22.12** or newer and use the **Enable workaround for simulate click with MV3 extension** option in [Project Settings](https://docs.uipath.com/activities/other/latest/user-guide/project-settings-ui-automation#browser).

## DeveloperToolsAvailability Group Policy limitations for value 2

The [`DeveloperToolsAvailability`](https://chromeenterprise.google/policies/#DeveloperToolsAvailability) policy has the following possible values:

* **0**: Disallows usage of the Developer Tools on extensions installed by enterprise policy. Allows usage of the Developer Tools in other contexts.
* **1** - Allows usage of the Developer Tools.
* **2 -** Disallows usage of the developer tools.

If the UiPath Extension for Edge is installed using [Group Policies](https://docs.uipath.com/studio/standalone/2025.10/user-guide/extension-for-chrome#install-from-group-policy), then `DeveloperToolsAvailability` is automatically set to **1** to enable full functionality of the extension.

:::note
This may be overwritten if your system administrator has set a different value for this policy.
:::

If `DeveloperToolsAvailability` is set to **2**, then the following limitations apply:

* The `InjectJS` activity does not work.
* The `ChromiumAPI` input method does not work.
* The UiPath Extension for Chrome is limited to LTS versions of `UiPath.UiAutomation.Activities`.

Other values for `DeveloperToolsAvailability` (**0** or **1**) do not affect the Edge extensions v24.10 or newer.

## The UiPath Web Automation browser window shows a warning

The UiPath Web Automation browser window shows the following warning if `ChromeNativeMessaging.exe` could not be started:

`Cannot communicate with UiPath Platform The native part of the extension is not configured correctly.`

Re-install the extension from UiPath Studio.

  ![docs image](https://dev-assets.cms.uipath.com/assets/images/studio/studio-docs-image-170256-d63b7c34.webp)

See [Check if ChromeNativeMessaging.exe is running](https://docs.uipath.com/studio/standalone/2025.10/user-guide/check-if-chromenativemessagingexe-is-running-edge#check-if-chromenativemessagingexe-is-running).

## The Inject Js Script activity can no longer be used to access page variables and code

By default, the **Inject Js Script** activity can no longer be used to access page variables, such as `jQuery $` , or to interact with page code (e.g., `window.alert`). The **Inject Js Script** activity won't report an error, but the script will fail to execute and the following error will be reported in the browser DevTools (F12): "Refused to execute inline script because it violates the following Content Security Policy directive."

  ![docs image](https://dev-assets.cms.uipath.com/assets/images/studio/studio-docs-image-172966-c3f61e55.webp)

This is a limitation introduced by the MV3 platform.

To fix this issue, select the **Execution world - Page** option from the **[Inject Js Script](https://docs.uipath.com/activities/docs/n-inject-js-script)** activity.

Your existing JavaScript code doesn't require any changes, and by using the **Execution world - Page** option it will work for both MV2 and MV3 extensions.

## Open Browser activity has an insufficient timeout

For MV3 extensions, the browser loads the extension later, after the web pages have loaded. This means that on slower machines, the **Open Browser** activity from **UiPath.UiAutomation.Activities** version 22.10 or older can reach the internal timeout of 20 seconds before the extension has started.

Starting with v22.12.0-preview, the internal timeout for the **Open Browser** activity has been increased from 20 seconds to 60 seconds.

Since you may need to set a longer timeout for the browser startup, it is now configurable from the **Use Application/Browser** and **Open Browser** activities. The following project settings have been added:

* **UI Automation Classic** → **Browser** → [Open browser timeout (seconds)](https://docs.uipath.com/activities/other/latest/user-guide/project-settings-ui-automation)
* **UI Automation Modern** → **Application/Browser** → [Open browser timeout (seconds)](https://docs.uipath.com/activities/other/latest/user-guide/project-settings-ui-automation-next)

Additionally, you can configure the timeout through the `UIPATH_OPEN_BROWSER_TIMEOUT_SECONDS` environment variable. For example, set `UIPATH_OPEN_BROWSER_TIMEOUT_SECONDS=120` to use 120 seconds for the activity's timeout.