In a MIDI track how can I change the colour of the dots representing notes to white, or some other colour that stands out? Sometimes, particularly on drum tracks the notes are almost impossible to see.
 
Thanks

Change the color of the MIDI track in track view.

Thanks but I can see no options there to change the colour of the notes in the track??

The track color can be changed by left-clicking on the colored vertical bar to the left of the track in track view. MIDI notes displayed in the PRV follow the track color, at least in the more recent versions of CbB. 
 
Different colors for tracks can be useful when editing complex MIDI arrangements. The more recent PRV improvements have helped as well.

For drums I sometimes resort to using the standard piano key display and set all notes to 30 so I can see them.

As I understand what joden means, you have to choose the mercury theme instead tungsten.

lapasoa
As I understand what joden means, you have to choose the mercury theme instead tungsten.

I believe that applied to the track strip color and not the MIDI note(s)/Wave form color (or what is referred to as the foreground in the Track View|Clips Pane|Clip section of the Theme Editor).  But the strip color option was addressed in the 2018.05 CbB update.
 
If you were to hover the mouse cursor over the color bar at the left end/side of the track strip in the TV (not to be confused with the Clips Pane) you will see it's hue/color change (or 'highlight' with the "Track Color" tooltip).  There you can left-click for the color palette to pop up (as Jackson described above) from which you may easily click on a desired color (or choose a custom color from the "Other..." button).
 
Kind regards,
 
tecknot