I'm an experienced C4D user trying to learn Houdini because it looks very capable to me and I want to add it to my toolset.
Currently I'm running into some issues with customizing the interface.

I can't figure out how to add more than one Shelf panel.
I know I can move the shelf to other panels, but I do not want that. I want multiple shelves on multiple panels. Or even a dedicated shelf panel that I can place in the UI so I can organize the buttons in a visual way.
Is there any way I can have multiple Shelf panels?

And an issue I ran into,
When I uncheck all shelf sets the self becomes black and I can't access the dropdown anymore. I think this might be a bug.
I'm using H21.0.729.