Hearing custom events

I maintain an add-in that needs to create a button on a spreadsheet that emits an event which is heard by an already instantiated class so that cached values can be taken advantage of. I seem to have no issue emitting the event, but it is never heard. I have created an example .xlam that replicates my add-in's core structure.

Step 1) Trigger RunMacro() to drop the button
Step 2) Click 'EVENT' button to throw event
When the event is heard, a message box should appear that says "Event heard: Custom_event_1 Cache is set"

What am I missing?
For those who can just look at the code to see what's wrong:

Please Login or Register  to view this content.

Please Login or Register  to view this content.

Please Login or Register  to view this content.

Please Login or Register  to view this content.

EDIT

I added WithEvents to the snippet in this post. I did not change it in the attached .xlsm. Anyone using the .xlsm for their own development will need to add WithEvents to the declaration.

Found it myself.

In the TestReader Class

Please Login or Register  to view this content.

should be

Please Login or Register  to view this content.

EDIT

I have changed this line in the above snippet for easier copypasta. Cheers.