Hi,
Yes, my description might be a little cryptic 
-the red rectangle is added afterwards from a paint program just to show where motion detection can be blocked to minime false detection.
-in your drop down menu in the picture above you have selected View and Motion. When that is selected and you are looking on the live view of the camera any movement will be market with red. That indicates what is triggering motion detection and a recording will start. It is a very good tool if you have a lot of false detections. If you change Algorithm in motion det configuration you can also see how it affects what triggers motion detection and a recording starts.
-“Will motion be detected or …”. In that transparent area motion will be detected.
-Henrik