Previously, touching a touch screen would advance the presentation to the next page no matter the cursor position. With this patch, this behavior can now be changed by a new option 'Tap Navigation' in 'Preferences->Presentation':
* Forward/Backward: Tapping on the left(right) half of the screen
makes the presentation go to the previous(next) slide.
* Forward: Tapping on the screen makes the presentation go to the
next slide, no matter where the screen is being tapped
* Off: Screen tapping doesn't do anything.
The actual action happens on mouse-release. For touch screens this means less interference with swipe gestures (which also allow to go to the previous/next page).