The UX changes based on how an end-user is selecting pending purchases in the 'Asset General Information' window.

If the user simply selects the drop-down list & select an existing purchase, they can subsequently add the class ID.

If the user select the 'Purchase' button from toolbar which opens the pending purchases window, the user cannot 'select' those purchases unless the Class ID has already been input.

Please provide the end-user the ability to open the purchase window, view existing purchases, select those purchases & then subsequently add the Class ID. In normal processing, the end-user doesn't know what the class ID for the purchase(s) is(are) until they view those purchases. Current process requires them to open the purchases window, close the purchases window, enter Class ID, open purchases window, select purchases.