How to fit text in a container?

Do you have an effect selected? if so which one?

Assuming you have effect selected, ticker will attempt to take the items you selected date and Description in this case and then attempt to show whole item (ie whole text in description for example).

If you have selected more items per page or if you’re not using effect then certainly some items might not be fully displayed.
Perhaps have a look here Here’s how to show as many ticker items as will fit and see if that would help you.