What's the use case for something like this? How often do you have a case where you say "the value changed and I need to change it again"? Doesn't sound like something that warrants this feature.
Just use latch action booleans! 😄 (if you cannot, use a local variable)
(In your particular case, you would also probably want to wire from the "oldval" without inverting, else it will flip the boolean if you would ever fire an event with the existing value wired to a signaling property of the control. Seems fragile.
I also don't understand the description of your idea. I don't see any tunnels anywhere. Please explain.
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