UINavigationBar loses alpha on size class change

Number:rdar://36233282 Date Originated:12/28/2017
Status:Open Resolved:
Product:iOS + SDK Product Version:iOS 11
Classification:UI / Usability Reproducible:Always

When a view controller experiences a size class change (like on iPhone orientation change), UINavigationBars with an alpha value of 0.0 will get reset to 1.0

Steps to Reproduce:
Setup a UIViewController in a UINavigationController, set it's navigationBar's alpha to 0.0, then rotate the device to trigger a size class change. Notice that the navigationBar's alpha becomes 1.0.

Sample app: https://github.com/obuseme/TestNavBar

Expected Results:
The navigationBar's alpha should stay the set value of 0.0

Actual Results:
The navigationBar's alpha becomes 1.0

Tested on Xcode Version 9.2 (9C40b), iOS 11.2, but present on other iOS versions as well



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