Why does popup not appear when I right click and drag from contacts to calendar?

I was showing someone how to create a Calendar appointment that includes contact information with the appointment (for sales people to schedule calendar events that have customer address in them so they can schedule their daily routes).  When I showed them on my laptop, it worked perfectly.  But, when they used their laptops (there were 10 laptops in the class I was teaching this) the popup did not appear.  Is this a setting, configuration, or option that needs to be selected before this popup appears?  this is bizzare.   here's a screenshot of how it looks when it works