# MouseTracker moved to rendering

> MouseTracker and related symbols moved to the rendering package.




:::important
These breaking change docs are accurate, as of the release
under which they are published. Over time, the
workarounds described here might become inaccurate.
We don't, in general, keep these breaking change docs up
to date as of each release.

The [breaking change index file](/release/breaking-changes)
lists the docs created for each release.
:::


## Summary

[`MouseTracker`][] and related symbols are moved from the
`gestures` package, resulting in error messages such as
undefined classes or methods. Import them from `rendering`
package instead.

## Context

Prior to this change [`MouseTracker`][] was part of the
`gestures` package. This brought troubles when we found out
that code related to [`MouseTracker`][] often wanted to
import from the `rendering` package.

Since [`MouseTracker`][] turned out to be more connected to
`rendering` than `gestures`, we have moved it and its
related code to `rendering`.

## Description of change

The file `mouse_tracking.dart` has been moved from the
`gestures` package to `rendering`. All symbols in the said
file have been moved without keeping backward compatibility.

## Migration guide

If you see error of "Undefined class" or "Undefined name" of
the following symbols:

* [`MouseDetectorAnnotationFinder`][]
* [`MouseTracker`][]
* [`MouseTrackerAnnotation`][]
* [`PointerEnterEventListener`][]
* [`PointerExitEventListener`][]
* [`PointerHoverEventListener`][]

You should add the following import:

```dart
import 'package:flutter/rendering.dart';
```

## Timeline

Landed in version: 1.16.3<br>
In stable release: 1.17

## References

API documentation:

* [`MouseDetectorAnnotationFinder`][]
* [`MouseTracker`][]
* [`MouseTrackerAnnotation`][]
* [`PointerEnterEventListener`][]
* [`PointerExitEventListener`][]
* [`PointerHoverEventListener`][]

Relevant issues:

* [Transform mouse events to the local coordinate system][]
* [Move annotations to a separate tree][]

Relevant PR:

* [Move mouse_tracking.dart to rendering][]

[Move annotations to a separate tree]: https://github.com/flutter/flutter/issues/49568
[Move mouse_tracking.dart to rendering]: https://github.com/flutter/flutter/pull/52781
[Transform mouse events to the local coordinate system]: https://github.com/flutter/flutter/issues/33675
[`MouseDetectorAnnotationFinder`]: https://api.flutter.dev/flutter/gestures/MouseDetectorAnnotationFinder.html
[`MouseTracker`]: https://api.flutter.dev/flutter/gestures/MouseTracker-class.html
[`MouseTrackerAnnotation`]: https://api.flutter.dev/flutter/gestures/MouseTrackerAnnotation-class.html
[`PointerEnterEventListener`]: https://api.flutter.dev/flutter/gestures/PointerEnterEventListener.html
[`PointerExitEventListener`]: https://api.flutter.dev/flutter/gestures/PointerExitEventListener.html
[`PointerHoverEventListener`]: https://api.flutter.dev/flutter/gestures/PointerHoverEventListener.html