Need a way to find position of a menu item by ID

[Wavesonics]

It's possible to get the ID of a given item by index, but not the other way around.

If we want to be able to use setSelectedIndex() to switch tabs programatically, and we don't want to rely on hard coded indices, we need a way to look up a tab position by ID.

Or better yet, also provide a setSelectedId() convenience method.