In your calendars we automatically have fixed headers turned on. This means that no matter how many Events or Day Notes that you've added to the days in your calendar, your calendar header (which shows the month and the days of the week) will stay in fixed to the top of your screen when you scroll down the page to view your calendar events. See the image below:
Note: In order for fixed headers to work you much have flexible row heights turned on and the "Disable fixed headers" feature turned off in the "Customize" screen for your calendar.
By default fixed headers are always turned on in your calendars. If you want to turn off fixed headers in your calendar follow the steps in the image below: