Removed 'default'

I wanted to avoid this behavior: 
1) tab through fields: nothing is added. 
2) Type a number in one and leave control
3) go back and remove typed number
4) *THIS* - zero or min appears 

I would like to be consistent with default behavior and not create not-typed values. This behavior also makes impossible to support optional numbers. Applied this fast fix of "" and worked, not sure about it.