Currently, when you right-click -> "Make Type Def" on a control / constant in a library VI, the new unnamed type definition is created outside
Also, it has the default control icon:
instead of a library control icon:
This leads to 3 additional tasks:
1. Drag and drop the control inside the library from the project explorer.
2. Edit the control icon to make it have the library control icon (with the horizontal slider glyph).
This is annoying because you need to copy it from another library control icon.
3. Go to the library properties and make "Apply Icon To VIs".
Bonus bug: If your new type contains a library-private subtype, the new control magically disappears from the project explorer when you click on it.
In comparison, the "Create SubVI" function works perfectly inside a library, i.e. it creates a VI inside the library and with the icon banner.
I think the "Make Type Def" function should behave the same to make library development more coherent and intuitive.