I found a workaround by adding a hidden vertical RuleMark for the beginning and end of the day. Not sure if this is a good idea but it does seem to work well.
RuleMark(x: .value("Start of day", period.start))
.foregroundStyle(Color.clear)
RuleMark(x: .value("End of day", period.end))
.foregroundStyle(Color.clear)
Topic:
UI Frameworks
SubTopic:
SwiftUI
Tags: