I'm thinking of an interface that will have a track bar which can have vertical lines of different colors drawn on it at certain points. I note that the track bar doesn't appear to have a Paint event, which seems to rule out my first thought, which was just painting onto the track bar itself.

Another possibility is to create my own. I did this for a slider that has a fish as the 'thumb button', so I could certainly do something like that again. That's a bit more of a nuisance, though, because my other custom slider didn't have (or need) the ticks on the standard track bar control. I'd like to have those, and the thumb button has to go over the extra color lines, rather than behind it.

Before I head off to making my own control, I thought I'd ask whether or not anybody has any other suggestion. The goal is a track bar with extra lines of emphasis that may or may not be on existing track bar ticks. The goal is to show a range of dates (the ticks), and indicate when events happened during that range of dates.