Managing proper Keyboard/input focus in plugins on macOS

[TheOnlyJoey]

Sorry if this feels like a duplicate (referring to #415)

I want to address this a bit more specific since it seems to be a problem that surfaces somewhat often.
The other issue described being able to toggle the keyboard focus if you want it to either take over focus, or never focus.
This is going more into a commonly expected default case.

Resurrecting this with a bit more 'complex' usecase.

For a couple of plugins i am working on, I have the problem that specifically on Mac (Logic, Reaper, Cubase) the focus is either fully grabbed, or with some patches ignored.
The problem is that we have components that require naming, typing preset names and a search bar.
So far the firstResponder hacks only help for setting it one or the other, is there anything specifically we can try to get the focus to shift based on if the plugin window has focus?

Also this behavior does not seem to be a problem on Linux and Windows as i can find so far. And DAWs like Bitwig behave properly in both cases it seems.

Originally posted by @TheOnlyJoey in #415

As originally described, one would assume that the functionality of input focus is handled the same as on Windows and Linux where depending on the window focus of the plugin, it would grab or release.
With actions like Search, Preset Names/Information, setting variables etc, its quite difficult to be restrained to either full or no capture.
This is also the default behavior for JUCE and other plugins on mac.

I understand this might be something to take up with PUGL, but just in case there is anything we can do on the DPF side, would like to start this discussion.
Thanks