I think there is an issue with the coral-select component when loading remote content. You can experience this behaviour on the help page Documentation | CoralUI
You need to jump to the "Loading Remote Content" anchor.
If you select a menu item and scroll down either using the mouse or the arrow-down key you will notice that the menu gets replenished by appending the same items over and over again. It turns out the coral-select:showitems event gets triggered when you reach the bottom of the menu.
