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Fixed in 1.0.0-preview.16



Found in [Package]


Issue ID




Mouse Enter Event is called every frame when moving another UI Element over the Mouse Enter Event area using Mouse Move Event

Package: Input System


How to reproduce:
1. Open the attached "InputIssueRepro" project
2. Open the Scene "SampleScene"
3. Enter the Play Mode
4. Left-click and drag the green square inside the red square

Expected results: Only one "Red square Enter Area" message is logged in the Console
Actual results: The "Red squareEnter Area" message is logged every frame the mouse is moved inside the red square while holding the green square

Reproducible with: 1.0.0-preview.6 (2020.1.10f1, 2020.2.0b9)
Could not test with: 1.0.0-preview.1 and earlier (the script wouldn't work), 2020.1.0b11 and earlier (UI Toolkit package version was not yet introduced)

- The issue is not reproducible when Active Input Handler is set to Input Manager (Old)
- Simply calling Mouse Move Event will not cause the Mouse Enter Event to trigger, only when actually dragging another object over the area will make the Mouse Enter Event to trigger
- The issue is with UI Element Events, does not reproduce with Event Handlers

Comments (2)

  1. 65022c4303542b686c0846ba14642a2b?d=mm


    Mar 28, 2021 23:20

    Any updates on when this might get fixed?
    This issue is still present in the most recent UITK preview (preview 14 with Input System version 1.0.2 and Unity 2021.1.0f1) . It is a massive roadblock for using UITK in combination with the new Input System.

  2. Cbaee4eb04d7e64531e651ca7d332a93?d=mm


    Jan 18, 2021 17:21

    I'm noticing a similar behavior where the MouseLeaveEvent is being called simultaneously with every MouseMoveEvent.

    Using: Unity 2020.2.0f1 + UI Toolkit

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