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