This depends on the underlying Calendar impementation which is FullCalendar, which does have an option for this (although I have no idea what exactly it does).
A quick non-upgrade-safe fix would be to uncomment this line here and then run Admin / Repairs / Rebuild JS.
You can also ask this kind user who recently had a very similar question to yours, to make that option configurable at the same time that he works on his own change and contributes it to core: