A document based process ideally would
- be fine and running without any document open. The File menu should let you then create a document
- let you open existing documents and should not mess around with whatever is already open
- ensure each document has their own meta data
On the Mac when you close the last open sketch this terminates the IDE process. If your plan was just to close something and go to your next project, you're toast and need to launch again the IDE. This is painful because it takes forever to launch (which seems to go slower and slower after each version - another frustration)
Also when you have a new sketch open and you started working a bit in it, but it's unsaved yet (like you are putting together a small example for the forum and don't care about saving it) - if you try to open up another sketch it will prompt you for saving or dropping the current sketch. Why the F#§$!ck does it does this? (yes it annoys me every time as you can see :) ) - I would just expect the other sketch to open in a new project and leave whatever I was working on alone...
I'd love to have Serial Ports and type of Arduino attached to a specific sketch. I've often 2 or 3 different arduinos connected to my Mac, compiling means always switching environments. Annoying (I could possibly run multiple instances but this is a poor workaround)