In the change log for version 18.0.323, it says

Dragging of primitives, selected or unselected, is now controlled by the active kind in the selector toolbar. We traverse up from the hit primitive to find a primitive of the desired kind. This means it's now possible to drag components, groups etc. even when they aren't selected.

Does this mean it should be possible to drag objects around without having to select them first? That would be great. But the only way I was able to move an unselected object was by selecting it first, hitting enter, and then unselecting it.

I reported this a while ago and it was already logged as bug #101432. I noticed that entry in the .323 change logs as well, but using the current production build .391 I don't see a change in behavior. You still have to: hit ‘s’, select the prim in the viewport, hit Enter. In effect Secure Selection is enabled without a way to disable it. Terribly clunky if you have more than a few objects and you're doing, oh I don't know… Layout work. You can treat the select shortcut as a sticky key and hold ‘s’ instead. That makes it more bearable, but it's definitely a change if you're not used to it.

I also logged an RFE for un-selecting prims by single-clicking in an empty area of the viewport (like in the standard scene viewer), rather than having to drag an empty area, or clicking a blank spot of the Scene Graph Tree.

I should make clear that this dragging of unselected primitives only works in physics mode. Is that what you're using?

Ah! no that's not what I was using at all. I was expecting the ability to be able to move objects around without having to select them first.
Ok good to now, thanks!

DaJuice
I also logged an RFE for un-selecting prims by single-clicking in an empty area of the viewport (like in the standard scene viewer), rather than having to drag an empty area, or clicking a blank spot of the Scene Graph Tree.

Happy to see this has been addressed in build .409

Fixed a bug with viewport selection in LOPs where click picking nothing would retain the previous selection, or previous highlight if area selecting.