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Fixed in 2022.1.X



Found in




Issue ID




m_RootOrder values change (or new ones appear) in the prefab when EditorUtility.SetDirty() is called on the prefab

Scene Management


How to reproduce:
1. Open user's attached project "" (when testing with 2018.4, open the attached "" instead)
2. Search (or manually navigate to "Assets\Art\Environment\Prefabs\Ground_Props\Independent\Nested") and select "IN_Cover_Furniture_2x1_W.prefab"
3. Use SetDirty() on the selected prefab (Flush > Selected Prefabs)
4. Compare the differences in files between "IN_Cover_Furniture_2x1_W.prefab" and "IN_Cover_Furniture_2x1_W-Original.prefab" (more info in the notes)

Expected result: "IN_Cover_Furniture_2x1_W.prefab" and "IN_Cover_Furniture_2x1_W-Original.prefab" files are identical
Actual result: m_RootOrder values of "IN_Cover_Furniture_2x1_W.prefab" are different from "IN_Cover_Furniture_2x1_W-Original.prefab", for example, "propertyPath: m_RootOrder value: 8" turns into "propertyPath: m_RootOrder value: 7" (in 2018.4.26f1 the previously existing m_RootOrder values stay indentical, while previously non-existent m_RootOrder code lines with their new values appear)

Reproducible with: 2018.4.26f1, 2019.4.9f1, 2020.1.4f1, 2020.2.0a21

- To compare the differences in files (step 4 in how to reproduce) Open Source program "WinMerge" (for Windows OS, download and run attached file "WinMerge-2.16.6-Setup.exe") can be used
- At the beginning both "IN_Cover_Furniture_2x1_W.prefab" and "IN_Cover_Furniture_2x1_W-Original.prefab" are identical
- "FlushChanges.cs" calls EditorUtility.SetDirty() on the prefab

  1. Resolution Note (fix version 2022.1):

    Fixed in: 2022.1.0a15

    m_RootOrder is no longer used to determine the sibling order of non-root objects

Comments (3)

  1. johanneskosanetzky

    Mar 23, 2022 10:44

    According to unity employee bugfix backport to 2020.3 was requested.

  2. marchall_box

    Jun 20, 2021 11:06

    I am getting this too. It's making the conflict possibility super high

  3. Kleptine

    Nov 10, 2020 00:34

    Can confirm, and it happens in scenes as well. Super annoying for conflicts!

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