Might be a good idea to call this something different in the Designer Properties and the Initialize Methods. I think it is confusing to beginners. An Event Prefix is what it really is. In a Event Sub like Button1_Click the Click is the Event Name and Button1 is the Event Prefix.
I'm also not seeing an easy way to know what an Event Prefix is that was set for a View. I do my designs by code so can scroll up and see what I set in initialize (Which itself isn't that great since now I lost my place), but for those that use the designer unless they keep the default name of the view they have to open the Designer each time for reference from what I can tell.
Would it be possible in the list that pops up when you type Sub <space> <tab> to have a different flow? Perhaps when you select a view like a Button the next menu is a list of Event Prefixes of Buttons defined in .bal files in the Files folder (Unless you can scan current Activity for current ones being loaded) and those defined in Initialize statements in current Activity, then the next menu is the actual Event list. That way there is no need for the typing the name and hitting Enter in the Green Box stuff.