Blueprints components setup through code cannot have the parent socket set inside the blueprint

If a component is created/setup through code and set as the child of a mesh component, clicking the magnifying glass in the Parent Socket field does not bring up the list of mesh sockets to attach the component to.

1. Open UE4Editor (first person template code project)
2. Open the FirstPersonCharacter blueprint
3. Click the Open Full Blueprint Editor button
4. Select the FP_Gun component
5. Click the magnifying glass next to Parent Socket in the details panel

Result:
Unable to set parent socket of the inherited component from inside the blueprint

Expected:
Doing the same steps in a Blueprint project will show the different sockets the FP_Gun can attach to.