It appears āwaveform fillā is responsible for making each color whiter/paler.
You can set it to black to not affect the color itself (so to speak), -just makes each waveform darkerā¦
It definitely would be nice if in the āColor Paletteā selector one could pick a transparent ācolorā⦠: /
But I donāt see how to do that for now.
I follow @GhostsonAcid advice and get this result choosing in preferences a dark color for āwaveform fillā:
What I want to modify is the ānormal stateā (not matter about selected, drag and so on states) waveform style, if possible without (or with less possible) vertical gradient gray/white.