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Won't Fix

Votes

0

Found in

2022.3.1f1

2023.1.0b21

2023.2.0a18

Issue ID

UUM-39920

Regression

No

ScrollView scroll speed decreases when an EventSystem is added to a scene

-

Reproduction steps:
1. Open user's attached “repro project” project
2. Open “SampleScene”
3. Enter Play Mode
4. Scroll up and down in the ScrollView

Expected result: the scroll speed is normal
Actual result: the scroll speed is very slow

Reproducible with: 2022.3.1f1, 2023.1.0b21, 2023.2.0a18
Couldn’t test with: 2021.3.27f1 (ScrollView disappears)

Reproducible on: Windows 11

Notes:
- Also reproducible in Standalone Player
- Disabling the “Event System” component in “[SCENE]\EventSystem” fixes the issue

  1. Resolution Note:

    Unfortunately, there is not much we can do about this, as we have a dependency there.

    We recently opened the ScrollView API to give control over the scrolling speed, so that users can adjust it based on their project's specific conditions. The attribute is `mouse-wheel-scroll-size`, or `mouseWheelScrollSize` from code (see https://docs.unity3d.com/ScriptReference/UIElements.ScrollView-mouseWheelScrollSize.html).
    This was added as an easier way to set the line height, that was previously supported with `--unity-metrics-single_line-height` in uss.

    Alternatively, if there is no use for the EventSystem with UI Toolkit (when not using UGUI at the same time as UITK), there is a way to manually disable interoperability with: `EventSystem.SetUITookitEventSystemOverride(null, false, false)`

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