I currently have the global shortcut set to ⌃ + Space. At the moment, pressing the global shortcut opens the command bar. If you then change your mind, you need to press Esc to close it. I have other Mac apps with globally launchable command bars and it seems like the convention is that if you retrigger the global shortcut, it then closes the command bar, like a toggle.

This has now become especially noticeable because I have a keyboard with many macro buttons that I've bound to global command bars for other apps. For those apps I can press the key once to open the command bar, and then press it again to hide it. With NotePlan I have to press one button to launch the command bar, then another button to close it.