Picklist bug or user error?

Picklist bug or user error?

I have a longish list of picklist values in a mandatory field. I have added a "None" value which I would like to be default, but as a new addition, it is added to the bottom of the list. I am trying to drag it back to the top, but the entire list keeps moving on my screen and will not allow display of the top of the picklist values. What am I doing wrong?
Additionally, I would like the user to have to select an item in the picklist, but it is accepting the word "None" as an acceptable answer (and in fact I would rather input "Select from options below..." instead of None.  How can I tell the system that any given value is a placeholder for a required picklist value?

Thank you