How to Adjust Business Hours
Displaying hours is relevant in Day and Week views. By default, the Business hours switch is enabled; only business hours are displayed.
Business Hours toggle active
Business Hours toggle inactive
IMPORTANT: Modifying which period is considered Business hours is only possible in Day view.
Display all hours by clicking - thus deactivating - the Business hours switch.
When all hours are shown, two arrows appear in the time row. 
Drag and drop the forward arrow before the hour desired to be the starting time of the Business hours period.
Drag and drop the backward arrow after the hour you want as the end of the Business Hours period.
When you activate the Business Hours switch again, the set time period will be displayed.
Adjustment of business hours is a custom setting for users: the status of the Business Hours Toggle is saved to the user’s profile.