Why am I sometimes prompted the message "The last item had over 200 coordinates"?

This message is a safeguard for users who convert to formats such as GDSII, which allows a maximum of 200 coordinates for each element.
Use the Library:Preferences:General menu to display the Preferences dialog box.
For the line that reads "Issue a warning if an Element having more than 200 coordinates is Put.", you can either disable the warning or increase the number of coordinates up to a maximum of 4096.