The column header height can be adjusted using the headerHeight property.
By default, column header height auto-fit is enabled. You need to turn it off when customizing the header height.
JavaScript
<div id="dp"></div>
<script type="text/javascript">
const dp = new DayPilot.Calendar("dp", {
headerHeightAutoFit: false,
headerHeight: 30,
// ...
});
dp.init();
</script>
ASP.NET WebForms
<DayPilot:DayPilotCalendar
...
HeaderHeight="30"
ColumnHeaderHeightAutoFit="false"
/>
ASP.NET MVC
@Html.DayPilotCalendar("dpc", new DayPilotCalendarConfig {
// ...
HeaderHeightAutoFit = false,
HeaderHeight = 30,
// ...
})