Vectors added to blueprint components don't display 3D widgets when the applicable options are set.

Component blueprints behave differently to normal actor based blueprints with regards to the show 3D widget option when a vector in the blueprint is set to editable.

Basically the 3d widget never shows in the main editor window because the vector is not a UStructProperty and fails tests in FEdMode::CanCreateWidgetForProperty to determine eligibility for showing the 3d widget.

1. Create a class blueprint based on Actor
2. Open the BP and add a vector variable
3. Mark it as editable and show 3d widget in the details panel.
4. Repeat steps 1 through 3 but this time use an Actor Component instead of Actor
5. Back in your Actor based BP click add component and add the blueprint component you just created to the initial actor class.
6. Drop in an empty scene and you should see that the actor class vector has a 3d widget in the main editor but the component vector does not.