When pickwhipping an effect while holding Alt/Option, After Effects refers to the property by index, eg. ("Slider Control")(1), instead of by property name, eg. ("Slider Control")("Slider").

I often use this, as I deal with clients in multiple languages, and the property index reference is more robust in this case. I would appreciate a toggle in Preferences to switch this behaviour so that using property index is the default for pickwhipping (no modifier keys needed), and property name is used when holding Alt/Option.