Bug 237675

Summary: Incorrect innerHeight IOS 15 Tabs "Single Tab" setting
Product: WebKit Reporter: Dan Bucholtz <dbucholtz>
Component: Layout and RenderingAssignee: Nobody <webkit-unassigned>
Status: RESOLVED FIXED    
Severity: Normal CC: bfulgham, simon.fraser, webkit-bug-importer, zalan
Priority: P2 Keywords: InRadar
Version: Safari 15   
Hardware: Unspecified   
OS: Unspecified   
Attachments:
Description Flags
Video of bug on iPhone 13 Pro none

Description Dan Bucholtz 2022-03-09 14:12:44 PST 
Created attachment 454284 [details]
Video of bug on iPhone 13 Pro

The `window.innerHeight` is not always correct in Safari 15 when the Safari setting for Tabs is set to `Single Tab`

Here is a very simple isolated example to demonstrate the issue:

https://ios-safari-scroll-position-bug.glitch.me/

Pre-reqs:
1. Using iOS 15
2. From Settings.app, In the Safari Settings, Set the `Tabs` setting to "Single Tab"

Repo steps:
1. Navigate to a web page that is tall enough to have scrolling enabled.
2. Scroll down enough such that the bottom safari "chrome" collapses
3. Click on a link/button to get to a page that's not tall enough to be scrollable


Expected behavior:

The Safari browser bottom "chrome" will remain collapsed, and `window.innerHeight` will give the correct value

Actual behavior:

The safari browser bottom "chrome" remains collapsed, but the `window.innerHeight` value is less than it should be





Additional notes:

1. You must be on a page long enough to scroll so that the bottom browser chrome collapses
2. The only way to get into this state if you have the nav bar collapsed on a previous scrollable page and then navigate to a page that is not scrollable
Comment 1 Dan Bucholtz 2022-03-09 14:49:04 PST 
Here is the Feedback link in Apple's system:

https://feedbackassistant.apple.com/feedback/9951903
Comment 2 Simon Fraser (smfr) 2022-03-09 14:56:29 PST 
Does this bug continue to reproduce in iOS 15.4 beta?
Comment 3 Radar WebKit Bug Importer 2022-03-10 10:17:06 PST 
<rdar://problem/90106441>
Comment 4 Dan Bucholtz 2022-03-10 13:10:24 PST 
(In reply to Simon Fraser (smfr) from comment #2)
> Does this bug continue to reproduce in iOS 15.4 beta?

I cannot recreate it in 15.4, so I believe this is fixed. Thank you!