Union Values in WPF

This morning I convered an enumeration from some VB code into a union in F#. This enum had been created so that I could create a generic "tab" view and view-model in WPF, and could easily tell each instance what tab it was to be. Unfortunately, I began receiving an error to the effect of The TypeConverter for "Tabs" does not support converting from a string. To solve this, I added an attribute to the union and a separate class definition; I can now set <DataTab TabType="Search" /> with no problems! Code below for my own future reference: