iOS version: 9.2
Original Bootstrap bug report: https://github.com/twbs/bootstrap/issues/17497
Steps to reproduce:
1. Open http://output.jsbin.com/qicigu/1 in iOS Safari.
2. Scroll to the bottom of the page.
3. Tap the "Open modal" button.
4. A yellow overlay appears.
5. Tap on the <input> that has the text "Click here".
The page scrolls to the top, the input becomes focused, and the on-screen keyboard appears.
The input should become focused and the on-screen keyboard should appear.
The scroll position of the page should not change.
No such scrolling occurs in Android Chrome or OS X Safari.
After you fill out the input and hit done the focus shifts to the background, modal stays up, and the background scrolls.