---
title: "Breaking: #77137 - JavaScript API of RTE changed"
manual: "TYPO3 Core Changelog"
version: "main"
permalink: "https://docs.typo3.org/permalink/changelog:breaking-77137-1668719172"
source: "Changelog/8.3/Breaking-77137-JavaScriptAPIOfRTEChanged.rst"
modified: "2026-09-14T09:47:36+00:00"
---

# Breaking: #77137 - JavaScript API of RTE changed

See [forge#77137](https://forge.typo3.org/issues/77137)

## Description

Due to the migration of the RTE from ExtJS to Bootstrap and jQuery, some API methods have been changed or removed.

## Impact

ExtJS-based plugins will throw JavaScript errors.

The following methods have been removed:

-   `onContainerResize`
-   `getWindowDimensions`
-   `setTabPanelHeight`
-   `syncHeight`

The following methods have been changed:

-   `openContainerWindow`
-   `buildButtonConfig`

## Affected Installations

All installations using custom RTE plugins are affected.

## Migration

The former `Ext.Window` objects are replaced by Bootstrap modals.

See the list below for a migration of the changed methods:

-   **openContainerWindow**

    The third parameter `dimensions` which used to be an array has changed to `height`, containing an integer

-   **buildButtonConfig**

    The method takes now two additional arguments: `active` and `severity`. The parameter `active` is a boolean
    value and declares the button being either active or not. The parameter `severity` is an integer representing the
    severity of the button. This should always represent the severity of the modal, use one of the severities defined in
    `TYPO3/CMS/Backend/Severity`.