Reply to Mapping Question

How can I turn off an effect if the button that turns it on if held is not held.

Basically I have a shift toggle fuction. If I press the button with shift toggled on, then an effect is toggled, if I press the same button without the shift the effect is only on as long as I hold the button. What I want is that the moment I press shift to return from toggle to hold mode the effect goes off.

I somehow cant figure how to do this, tried quite a few times.

Thanks for any help!