Utility window that listens to input events to set a key binding. Pressing a key or mouse button will define the binding and then immediately close the popup.
public class KeyBindingPopupWindow : EditorWindow
The shift keys don't raise input events on their own, so this popup does not work for shift keys. These have to be bound by selecting from the traditional dropdown list.
Create a new popup.
public static void Show(SerializedProperty keyBinding)