In the Fields editor I know the fieldslistclose event fires when the Field Editor is closed either by clicking on Apply or Cancel. How can I tell which button was clicked.
Unfortunately, the fieldslistclose event doesn’t have information about button clicked. I recommend you compare slices before and after the click. If Cancel was clicked nothing is changed in the report’s state and they should be equal.
Please use getReport() call to get the active slice.
Does it help?