Exposure bug ?

I suppose there is some background magic I don't really understand. 

I'm trying to set component's exposure to get down in the hierarchy, but as soon as I override this property with

Public Overrides ReadOnly Property Exposure As GH_Exposure
Get
Return GH_Exposure.quarternary
End Get
End Property

It just disappears from the drop-down.

This is just a simple component I'm trying to add to an existing panel (The current icon is just a placeholder).