I noticed, that unless I’m connected to a machine of some sort, I can’t do anything.
It’d be nice if I could at least edit macros .
Plus, maybe a better “console window”, for editing macros. Like testing ability, ability to use variables as if they were in the macro, but not actually running. (it’d be nice to test a line for syntax, but without actually connecting to/using a machine, so I can see if I’m getting errors on basic stuff)
I use Notepad++ on Windows for editing (or any other text editor.)
I also recommend that you be very careful with executing macros on your hardware until you know you aren’t going to send it to the moon at high speed! 
Perhaps use ncviewer or something similar?
EDIT: I forgot to say that then I save it and uploaded it to the macro editor.
I always have an Arduino or ten laying around. I try to keep one loaded with Grbl for these reasons. No one needs to know that there’s nothing actually connected to the controller, but it’s great for testing things, checking gcode, and testing new versions of gSender.
I’m the same as NeilFerreri. I have one hooked to my home computer to check changes etc. in the house before I try them on the CNC in the shed.
How can you tell when the gcode sends the “machine” to an out-of-bounds area?
I have an Arduino mini (or micro?) connected up, and that does work, but it be nice to be able to not “have” to have it out there. One good thing about it, is I don’t have to worry about crashing the machine with a “stupid” G-code command!
And I do use Windows text editor some times, simply because it’s easier to see, and has a little bit better editing commands (like cut and past, with the mouse instead of keyboard only).
On most machines, you can enable “soft limits”. Then, when the controller receives a G-code command that will move the head outside of those limits, you will receive an error. Doesn’t matter if an actual machine is connected or not, an Arduino mini will work just fine there.