There is no need to look into this matter any further.
I was adding the schedule component to a project I was working on and had included the "default.css" as indicated in a previous answer but the corrupt dropdown items were showing,
I then looked at the sample at jsplayground and found that it was not working either.
However, in my project I am using "w3.css" (http://www.w3schools.com/w3css/) and when I removed it the scheduler worked correctly.
I will investigate what is causing the conflict so that I can use the "w3.css" with the scheduler.
Sorry for any inconvenience.
Morgan