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Fixed in Unity 2018.3



Found in


Issue ID




Canvas Group Alpha does not affect nested Canvas UI elements when used in parent Canvas




Priority: 2Necessary for shipping a final release


Severity: 3Secondary functionality broken

How to reproduce:
1. Download, extract and open attached project (
2. Open 'SampleScene'
3. Modify Canvas Group Alpha in the 'Parent canvas' Canvas to see the issue

Expected result: Both buttons are affected by the Canvas Group
Actual result: The button that is the child of the nested Canvas is not affected unless the Alpha is 0

Reproducible with: 2018.3.0f2, 2019.1.0a13
Not reproducible with: 2017.4.18f1

Fixed in: 2018.3.8f1, 2019.1.0b3, 2019.2.0a5

Comments (5)

  1. 9c7dc0508716142543de1cbf4102d7c3?d=mm


    Feb 22, 2019 08:29

    It is a very very serious issue, Unity! Also, Unity 2019.1 is in the beta stage, so it can't be say fixed. If this is not fixed into 2018.3.X, it's going to be a problem for so many projects.

    Our projects have a lot of contents, and on live. And we upgrade Unity 2018.3.0f2 from LTS for wasm boost one month ago. So we'll decide revert to LTS(it maybe a very hard way) or fix it using dirty ways. Please, answer anythings.

  2. 8073ef065add2a44afc405a841a5e1d0?d=mm


    Feb 14, 2019 07:15

    This is causing me issues too. Any update on backporting this?

  3. Dbdbcb17c7a1ab3547e6bd2c8c5f3c35?d=mm


    Feb 07, 2019 01:56

    This totally messes up my UI hierarchy and logic. I added nested canvases to improve performance following your guidelines, only to enter another world of problems. Now I have to rewrite my UI handling scripts and they will turn into a mess. This MUST be backported ASAP, I'm using 2018.3.4 and it breaks. Please make me happy and backport it in 2018.3.5 (2019.2, WTF???)

  4. D59cf1626a46b2ed83ce5c6fe7f44616?d=mm


    Feb 06, 2019 21:35

    I see this is fixed in 2019.2, is this going to be back ported into 2018.3.5? Or is there not going to be a 2018.3.5, and the next actual release will be 2019.2? I'm still not clear how the new versioning works. All know is that this bug is buggin' me!

  5. D59cf1626a46b2ed83ce5c6fe7f44616?d=mm


    Jan 25, 2019 16:12

    Any idea what version this is fixed for?

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