Bring back the keybed graphic in combinator

[aMUSiC]

In Combinator 1, in the Editor mode, there was a keybed graphic which would visually depict the range of notes that a device could receive. This made it extremely useful and quick to set the ranges. However in Combinator 2, this has been removed in favor of the arrow sliders which are very hard to use, especially when using non-mouse input methods for the cursor (such as trackpads, touch screens, pens etc).

I'd like to see that brought back to Combinator 2, with the addition of a couple of quality of life features:

- Be able to click on the exact key on the keybed graphic to set low/high ranges
- Be able to assign low/high ranges by pressing the corresponding keys on a controller

[stillifegaijin]

Yes, I agree.