On a normal sized screen: Open the following dialogues and confirm that the scroll lock is active: Activity chooser File picker A confirmation box (e.g. delete activity) Make your window height much smaller so that it is smaller than the dialogues (this probably won't be possible with the confirmation), but keep the width normal Repeat, confirming that the scroll lock was not enabled Make your window width smaller too Repeat confirming that the dialogues were shown full screen Confirm that the when you scroll and then close the dialogue, the background window has not changed. Note: In testing this, I discovered that iOS does not handle the scroll locking in the same way - it completely ignores the body overflow property. Test edit pdf in different screen sizes and verify you can always get to the submit buttons at the bottom of the dialogue.