As can be seen in https://github.com/scottjehl/Device-Bugs/issues/8 a combination of "-webkit-overflow-scrolling:touch", "position:relative" and "overflow:auto" can have unexpected behavior on iOS. The issue solved here is that writing in a form view inside a modal in iOS (at least version 10.3) would make the whole form body invisible until edition is ended. This commit fixes this by adding a CSS rule which avoid the iOS bug. opw-774396 closes #20314