Bug 182709

Summary:

Elements placed using position: fixed are misplaced when contentInsets are manually set in WKWebView

Product:

WebKit

Reporter:

Zach Waugh <zwaugh>

Component:

Scrolling

Assignee:

Nobody <webkit-unassigned>

Status:

NEW ---

Severity:

Normal

CC:

simon.fraser, thorton, wenson_hsieh

Priority:

Version:

Safari 11

Hardware:

iPhone / iPad

OS:

iOS 11

Attachments:

Description	Flags
Sample Project	none

Description Zach Waugh 2018-02-12 15:03:52 PST

Created attachment 333634 [details]
Sample Project

When a WKWebView is configured with `webView.scrollView.contentInsetAdjustmentBehavior = .never`, DOM elements using `position: fixed` are misplaced. This occurs even though the correct contentInset has been manually applied. When `webView.scrollView.contentInsetAdjustmentBehavior = .automatic` (or not changed), it works correctly. This applies when the web view sits beneath the nav/tab bars. It works correctly if the web view does not underlay nav/tab bars in either configuration.

I've attached a sample project that demonstrates the bug. It is also available on GitHub - https://github.com/zachwaugh/wkwebview-bugs/tree/master/PositionFixedContentInset