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Fixed in 2019.1

Fixed in 2019.2



Found in





Issue ID




A Performance Issue appears when Brute Force Sorting a large amount of UI Objects with Canvas Component



How to reproduce:
1. Open the "SampleScene" Scene in the attached "New Unity" Project
2. Click on the main "Canvas" GameObject
3. Enable the Canvas Group Component
4. Click on the "SortByName" and "SortByValue" Buttons in the Game View
5. Observe the Editor stuttering once you click on the Button

Expected Behavior: The UI Object sorting is as fast or slightly slower than without Canvas Group component enabled
Actual Behavior: The UI Object sorting is a lot slower than without Canvas Group component enabled

Reproducible with: 2019.1.0a9, 2019.1.1f1, 2019.2.0a14, 2019.3.0a1
Not reproducible with: 2017.4.26f1, 2018.3.14f1, 2019.1.0a8

Note: UIBehaviour.OnCanvasGroupChanged() is called nearly 1m times when sorting 100 UI elements. The number goes down to around 0.12m when you change the UI element counter to 50.

  1. Response avatar

    Resolution Note (fix version 2019.1):

    Fixed in 2019.3.0a4, backported to 2019.1.0a5, 2019.2.0b4

Comments (2)

  1. D0a6f3677b502b95a1fe547d33cfb938?d=mm


    May 10, 2019 11:45

    This article is really helpful. I Really don't know much about the topic. It would be really helpful if you could describe this. I think it is something related to brute-force. In cryptography, a brute-force attack consists of an attacker submitting many passwords or passphrases with the hope of eventually guessing correctly.

  2. 597bc288708136c546f4a5b2b261b35d?d=mm


    Apr 27, 2019 05:09

    That's a problem which can make someone go mad.
    Have you tried speeding up your system. The problem might not actually be from the software.

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