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Votes

0

Found in

2018.3.0a1

2019.1.0a1

2019.1.0f2

2019.2.0a1

2019.3.0a1

Issue ID

1149053

Regression

No

MoveMouseEvent.button returns 0 both when no button is pressed and when the left mouse button is pressed

UI Toolkit

-

How to reproduce:
1. Open the attached "case_1149053-MouseMoveButton.zip" project
2. Open the "BugReport > ExampleWindow" window
3. Move the mouse around in the "Actual Behavior" box, notice that MoveMouseEvent.button returns 0
4. Move the mouse while holding the left mouse button around in the "Actual Behavior" box
5. Inspect the MoveMouseEvent.button return value

Expected results: MoveMouseEvent.button returns different values when moving the mouse with or without clicking the left mouse button
Actual results: MoveMouseEvent.button returns 0 both when moving with and without clicking the left mouse button

Reproducible with: 2018.3.14f1, 2019.1.1f1, 2019.2.0a14, 2019.3.0a1

Note: Could not test in 2017.4 due to missing namespace errors.

  1. Resolution Note (2019.3.X):

    Hello,

    As of today this an expected behaviour and the issue is a shortcoming of our current API.

    This comes from the fact that the "button" property reflects the native event "button" property for which "0" means left.
    https://docs.unity3d.com/ScriptReference/Event-button.html

    However UIElements translates both MouseDrag and MouseMove native event types to the same MouseMoveEvent object.
    The "button" property is only meaningful for Drag events, so the suggested workaround to read the underlying native event type to detect a proper drag:

    For example testing with "evt.imguiEvent.type == EventType.MouseDrag" will work.
    https://docs.unity3d.com/ScriptReference/UIElements.EventBase-imguiEvent.html

    In 2019.3 we will introduce a more usable API which will expose a bit mask to test for pressed buttons.

    Thanks for reporting this issue, hopefully this will do for now.

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