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Fixed in 2018.3.X

Fixed in 2017.4.X

Won't Fix in 2018.1.X, 2018.2.X

Votes

4

Found in

2017.3.0b3

Issue ID

957857

Regression

No

Assertion failed on expression: 'modifications.empty()' when Dragig Droping a Prefab into the Hierachy

Themes

-

To reproduce:

1. Download attached project "Unity UI Bug.zip" and open in Unity
2. Open "Bug Scene" scene
3. Drag and Drop "Object Content" prefab into the Hierarchy
4. Observe that Console throws an error:

Assertion failed: Assertion failed on expression: 'modifications.empty()'
UnityEditorInternal.InternalEditorUtility:HierarchyWindowDrag(HierarchyProperty, Boolean, HierarchyDropMode)
UnityEngine.GUIUtility:ProcessEvent(Int32, IntPtr)

Notes:
- Workaround: Drag and Drop "Object Content" prefab into the Hierarchy, Rename this prefab, create a new prefab and next time, when you Drag and Drop this newly created Prefab, no error will be thrown.

-It is occurring only when we drag and drop canvas prefab into the hierarchy

Reproduced on Unity 5.6.4f1, 2017.1.2f1, 2017.2.0f3, 2017.3.0b4, 2018.1.0f1 and 2018.2.0b1
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Comments (6)

  1. SpeedOfLint

    Dec 16, 2018 11:31

    Can still be reproduced in 2018.2.15f1.

  2. qd19218960

    Sep 07, 2018 02:43

    Can reproduce on 2017.4.10f too.

  3. xieyun2017

    Sep 03, 2018 09:40

    it happened in 2017.1.5f1

  4. carldevelopsforcoffee

    Aug 08, 2018 06:04

    getting it in 2018.1.3f1. Dragging a prefab with a canvas into the scene as a child of another canvas causes this. The dragged object then will have its rect transform messed up.

  5. manoj514

    May 15, 2018 10:57

    this issue is not fixed and I am facing it in 2018.1.0f2

  6. anuragaofl

    Jan 24, 2018 18:23

    Can reproduce on 2017.2.1p2 as well.

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