As discussed in
CCs colors, why all black in the end?,
MIDI Color Map Explanation and other threads, "Color by track" and "Color by item" are not well implemented:
* In the active item, only the insides of notes and CCs are properly colored, while the border has some unrelated color. (I am not sure how this color is selected. It seems to be black for unselected events and some lighter color for selected events.) When CCs are drawn densely, the track or item color is obscured by an solid block of border color:
* All tracks use the same border color, so dense CCs from different tracks cannot be distinguished.
* In inactive, only-visible items, notes and CCs are drawn with slight transparency, which is a good idea to make only-visible events less prominent -- except that the brightness of overlapping transparent events adds up and eventually dense CCs in visible items are much brighter than CCs in editable or active items.
Interestingly, in inactive, editable items, the border color seems to be a darker shade of whatever random color is used for that item. This is a much better solution.
In this image, the track color is red, and the items from left to right are visible, editable and active. The visible item appears most bright and "active":
* When events are selected, the border color of the active item is different than that of editable items on the same track, leading to further confusion:
Suggested solution:
* Borders colors should be derived from track or item color, similar to editable items currently.
* Overlapping transparent events should not accumulate brightness.