Actions on playing video

What happens when I play (fullscreen) a video, fe by pressing OK on movie name in MyVideoNav (I am looking at Estuary)?

I imagine it goes like this:

– Kodi plays video full screen
– Now I press OK on remote
– Kodi activates VideoFullScreen and populates VFS’ fields with some magic (from manual):
1 label Numpad seek label
10 label Line 1
11 label Line 2
12 label Line 3
– Kodi activates VideoOSD

What I would like to know:
– how pressing OK causes Kodi to load VFS and VOSD? Is the event sent by OK when playing fullscreen video somehow linked internally in a fixed manner to activating/deactivating these two windows?
– what are VFS fields populated with?
– I noticed “back” remote button does not end playback – how to achieve such behaviour?