PS to LrC

While such roundtrip edits are possible, I would not recommend it unless you're absolutely clear on what happens when you do.

Most importantly, Lightroom does not support layers. What you see in Lightroom is a merged composite that Photoshop inserts in the file. Any Lightroom edits at this point are done to this flattened composite. Layers from Photoshop are still there in the file, but Lightroom can't read them or do anything about them.

If you want to use the Lightroom sliders later, you can do it with the ACR filter in Photoshop - and then you also have access to the Photoshop layers, you can use smart objects, etc. Otherwise it accomplishes exactly the same thing. Win/win.

In short, roundtrip editing is a recipe for confusion and mixups. After a while you no longer know what edits were done where or how you get to them. Correcting one edit messes up the others.

If you edit a photo in Photoshop (using the LR command "Edit in Photoshop...") and save it in PS the photo is inserted in Lightroom. After that it can be edited in Lightroom.

Why you would have a dropdown menu? It isn't necessary.