We recently have implemented a new Picking application in our warehouse. Our slow performing statement e-mail has immediately highlighted that with our data volume the WMSOrder and SalesTable records were underperforming, taking 5+ seconds each time when the form was opened (close to 20). We needed to fix the Picking list registration performance.
Apparently it is a standard AX form and table, but the link which they have been using is incorrectly defined, resulting in an InnerJoin for SalesTable unnecessarily.
Also the field used for the join has no index, you should create one for WMSOrder.InventTransRefId to gain more performance.
After the adjustment it looks much better and performs really fast: