Creating a Button List to send a unique value from each

In the generic button click event there has to be code to test if the button already has a click event handler, to head off conflicts.

There is a generic event parameter for that: notAlreadyHandled.

Wrap the generic code with an
If notAlreadyHandled then
Do the generic stuff
block.

Some people use an Is component in List test in the generic event.

There is nothing you can do in the specific button component event to control this.

Sample app: