Hi,
Thanks for reaching out about this question. The picking in the scene view is render-based, so it's expected that a GameObject with a collider only cannot be selected. This would complicate a lot more the selection, if for example you build a scene with a lot of containers around the content (to keep physical objects inside an area for instance), the selection would then pick a lot of undesired invisible objects when trying to select an object inside the colliders.
However, several options are available to enable selection of objects without renderers in the SceneView.
- The first one would be the use of Icons on the desired GameObjects:
https://docs.unity3d.com/6000.1/Documentation/Manual/InspectorAssignIcons.html
This way you can easily visualize them and select them, while adding a label to them or a custom icon (This is for example how you can select lights or Cameras in the Scene).
You could also design custom gizmos and add them to your GameObjects to be able to visualize them even when they are not selected, and add selectable capabilities on them, this would for instance allow you to visualize a collider area without even having to select the object itself:
https://docs.unity3d.com/6000.1/Documentation/Manual/gizmos-handles-programming.html
I hope this will help you!
Have a great day.