Advice on subclassing KeyboardKey?

[otbox21]

I'm making a keyboard with another view that will have some snippets. I'm starting with just 8, like this:

I'd like to have these buttons behave like the normal keyboard keys do, with their wonderful pop-up behavior and their proper resizing across devices and all that. So, I figure I should make a subclass, like class SnippetKey: KeyboardKey

There's coding wizardry on this keyboard the likes of which are a bit beyond me, so I learn by changing things here and there, guessing, and then actually seeing what it does. So, I went into DefaultKeyboard, and changed the QWERTY row to just three keys, hoping that they'd magically display like my above picture. They did this:

Any advice would be very much appreciated. Until then, I'll be poking and prodding the code. Thanks!