Can you close a file without quitting Rhino if there is just one file open?
Rhino is not a multiple document application. If Rhino is open there is one file open in it.
You can have as many Rhino sessions running concurrently on your computer as you have resources to support them. For most people, two or three concurrent Rhino sessions works fine.
Sure, just hit the “New” button.
The New button is close to what i want.