Add property creates properties with the same name

[roddolf]

When clicking multiple times the Add Property button, several properties will be added, but every one with the same name New_Property_1.

Since that there is a number that indicates the index of the new property, it may expected to have a list of properties with the names: New_Property_1, New_Property_2, ... New_Property_n.

[AlexSerrano22]

this issue is related to #161