I meant specifically within Moon+ Reader Pro, which is my e-reader on Android. I wonder if the 3 Android buttons will now "fade out" automatically, which would be great, or if the developer of Moon+ Pro Reader must first adjust his software so that it uses this new Android 4.4 capability. I have no way to test this right now, as my Nexus 7 reports Android 4.4 is not yet available for download.
Moon+ Pro Reader offers its own internal swipe-up and swipe-down gestures, so this likely means I will need to disable them to avoid conflicts with the new "Immersive" mode.

I would prefer the following mode of operation:
- Tap your finger in the center of screen, the 3 Android buttons pop up.
- Tap again, Moon+ toolbars appear.
- Tap again, Moon+ toolbars go away.
- Tap once more, the 3 Android buttons go away, too.
The first three steps already work like this in Android 4.3; but to make the 3 Android buttons go away in the final step, you currently need to press the
volume button to turn the page; and that's annoying.