A context menu can hold all sorts of useful things (could even be configurable):
New, delete, duplicate, select layers (in the panel), select objects, … the usual.
Btw. icon’s aliasing is a little ‘unclean’. Maybe only seen in dark mode.
A general note:
This new Object Manager, in a way, ‘includes’ the Layer panel (and others), right? I believe you mentioned somewhere that the Layer panel, too, is re-written (or at least ETO-ified).
Can’t both be one and the same? Spare some work and go for a ‘unified’ solution?
A little inspiration, on that behalf: I used to work with Softimage XSI a few years, which had exactly this: a unified Scene Explorer, which could hold everything, the 3d scene, layers, materials, lights, passes…
You just needed to roll over the panel, and press any filter key (L for layers, S for scene root…), and there you go. There could also be many Explorers, each of which could be locked and used for drag&drop.
Why am I telling you this:
XSI’s UI was amazingly efficient and ‘compact’. Best in class (on top of being a brilliant animation program and very good poly modeller). Not because the UI had so many bells and whistles, but because it was so ‘generalized’ and logical. Cinema4D and Blender come close, but not really. Although XSI was for a different industry, many UI principles can of course be ‘laid over’ any other 2d or 3d application. They were really ahead of their time (still chucked in favor of Maya by Autodesk).
You might want to give it a thought to ‘generalize’ Rhino’s UI, too, one step at a time. Why are so many panels for different things necessary, when just one do-it-all-panel would suffice, and switching the ‘mode’ is just one tap on the keyboard? Since you are at it…
Thanks for reading!