Answered: I recommend checking the data - it may contain invalid items which break the view. You can also check the JavaScript console to see if there are any errors.
Answered: Unfortunately DayPilot Pro is only available for ASP.NET WebForms. It's possible to run the WebForms version in a WinForms application using an embedded browser (WebControl), but it's just a workarou...
If I want to add a calculation can you show me how? I downloaded the full booking system but for my school project, the system should have some sort of a calculation!
Answered: Only by displaying the control using a WebBrowser component. Take a look at the following tutorial: https://code.daypilot.org/70282/daypilot-in-a-desktop-application-winforms
Answered: The DEMO label indicates that you are using a trial version of DayPilot Pro (which is bundled with the tutorial). In order to remove it you need to purchase a full license at http://www.daypilot.org/...