Missed keypresses in plugin UI

[peastman]

I'm implementing the UI for my plugin with egui and testing it in Reaper on macOS. It includes a text field for the user to type into. It doesn't work correctly. When I try to type into it, Reaper intercepts the keystrokes and interprets them as commands instead of sending them to the text field.

I found reports of the same problem in other VSTs:

https://forums.steinberg.net/t/how-receive-computer-keyboard-keystrokes-in-vst3-plugins/700967

iPlug2/iPlug2#477

Based on those reports, I believe the problem is that NIH-plug doesn't implement on_key_down() and on_key_up():

nih-plug/src/wrapper/vst3/view.rs

Lines 339 to 355 in 16c6c58

	unsafe fn on_key_down(
	&self,
	_key: vst3_sys::base::char16,
	_key_code: i16,
	_modifiers: i16,
	) -> tresult {
	kNotImplemented
	}
	unsafe fn on_key_up(
	&self,
	_key: vst3_sys::base::char16,
	_key_code: i16,
	_modifiers: i16,
	) -> tresult {
	kNotImplemented
	}

Returning kNotImplemented tells the host that the plugin isn't interested in keypresses, and the host should interpret them itself.

The CLAP version of the plugin has the same problem. I assume it has a similar mechanism.