With the introduction of this new system preference UpdateItemLocationOnCheckin, the cart to shelf system preference was removed and rolled into this one. However, the alert that comes along with this new system preference is not a welcome addition to the libraries that are using Cart to Shelf functionality. Prior to this, cart to shelf functionality was a backend process that would (without staff interaction) take an item that was checked in, move it to the cart. Now, when an item is checked in (at the system preference UpdateItemLocationOnCheckin has the value _ALL: CART - each time an item is checked in, the staff get a large yellow message box and an alert. If we add a class to this message or even 2 classes this would allow these alert/audio to be turned off for those libraries that don't wish to receive this yellow alert box with every checkin.
I don't think this is valid any longer? On master, these messages get the class "ret_location_updated." As far as I can tell, that's only used for UpdateItemLocationOnCheckin messages.