Scroll Wheel Delta

How do I get the input data of ScrollWheelDelta to be 0 when the scroll wheel is not being moved? I am trying to allow the player to zoom in and out using the scroll wheel, however the camera continuously zooms in or out until scroll input changes due to the value of the previous scroll being kept instead of returning to 0. Is there a way to fix this issue or get around it?

Wich version you use, GD4 or GD5 ?

If you wait the next release of GD5 you will be able to use the new condition “mouse wheel scrolling up/down”.
Each notch of the mouse wheel return true or false is more simple to use. Value is reset to false if scroll don’t move.