White line appears at top of screen in full screen mode

Originator:gnachman
Number:rdar://FB8884688 Date Originated:11/5/2020
Status:Open Resolved:
Product:macOS Product Version:11.0, 11.1
Classification: Reproducible:Always
 
When my app is in full screen on Big Sur and the theme is light mode, a white line appears occasionally at the top of the screen.

I have a titlebar accessory view controller. This has been flaky during Big Sur, so my guess is that it’s involved.

To reproduce:
1. Install iTerm2 3.4.0beta13 from https://iterm2.com/downloads, or clone https://github.com/gnachman/iTerm2 and checkout commit 08faffe83b2209ad5b8f5196b7b116a485317d65 then build & run in Xcode.
2. Enter full screen mode
3. Type for a while. A white line periodically appears at the top of the screen.

You can see a screen recording here:
https://gitlab.com/gnachman/iterm2/uploads/162bbc892099299d0f55eccce611446a/Screen_Recording_2020-10-19_at_9.58.57_AM.mov

I am able to reproduce this easily on my own machine. I captured the view hierarchy (attached) and it does not appear there.

I have tried removing the title bar accessory view controller, but that does not solve the problem.

[sample project at https://iterm2.com/misc/whitebar.zip]

Comments

Still happening for macOS Monterey

By joel at Oct. 31, 2021, 11:14 p.m. (reply...)

iterm2 Build 3.4.4, Big Sur 11.2.3 (20D91) The problem still happens, and very annoying. I can't imagine Apple allows this bug to exist for such a long time. It doesn't help your users to have confidence in Apple product's quality.

By sapience at April 1, 2021, 8:01 a.m. (reply...)

This bug still exists, Hope this is being fixed. In the meanwhile, is there anything that App owners can do as a workaround fix for this?

By manideep.bvs at March 8, 2021, 3:40 a.m. (reply...)

As of today this bug still exists, quite annoying to be honest.

By hamza at Feb. 26, 2021, 10:57 a.m. (reply...)

This affects me, too. Quite annoying.

By adamgeorgiou at Feb. 23, 2021, 6:19 p.m. (reply...)

iTerm Build 3.4.3 and macOS Big Sur 11.2 still happens.

By gabriel.sobrinho at Feb. 8, 2021, 3:21 p.m. (reply...)

Up to now, the bug stills exist

Report Build 3.4.20210125-nightly Mac Big Sur 11.1 This bug still exists. The only work around works for me is using dark mode. Well, I used to use light mode even at night, hope this to be fixed soon.

By hailiang.hl.wang at Jan. 28, 2021, 4:12 a.m. (reply...)

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