Small suggestion: In the case of selecting an item that's not the topmost, it would be nice if it was a one-step process rather than two (you need to first highlight with ctrl+letter, then activate with Enter).
Maybe a repeated press of ctrl+letter could actually activate the selection. Or maybe pressing and holding ctrl+letter for a short while.
The reason why I'm currently making users explicitly use Enter/Return to click is because this allows them to use modifiers while clicking, so Ctrl+Enter for right click, Cmd+Enter on a link to open it in a new tab, etc. However, I think Ctrl+letter might be interesting, but might be confusing on multi-letter shortcuts.
Small suggestion: In the case of selecting an item that's not the topmost, it would be nice if it was a one-step process rather than two (you need to first highlight with ctrl+letter, then activate with Enter).
Maybe a repeated press of ctrl+letter could actually activate the selection. Or maybe pressing and holding ctrl+letter for a short while.