[Robin Palmer]

The name of PC wavedorm monitor and vectorscope is Vidscope-VX
https://www.vidscope-vx.com

The reason for the gaps is the RGB histograms are the missing values after you have done a contrast stretch. This is quantisation and would be hard to see on moving video useless the stretch is extreme.

The quantisation errors may be seen as horizontal striations on a waveform monitor. When a contrast stretch is extreme it can lead to illegal levels (gamut errors) unless clipping or correction is applied afterwards – but the gaps will remain.