Hello! I used the css-class .free to change some background-colors to green. When the page loads for the first-time the Calendar remains white,  my customers cant see what time-slots are available. When i change the month in the calendar ,the class .free appears in the sourcecode and the correct background-colors as well.   Why does this happen ? btw the domain is http://davidvanl.de/massanzug/  thank you very much(: