To check a barcode in the staff interface in Koha you need to go to the detail screen. In the results list you have access to a lot of item information like callnumbers, check-outs, locations, etc. but not to the barcodes. It would be helpful to some libraries to be able to check barcodes in the results listing. Koha should be able to turn this feature on or off since some libraries could prefer the actual result listing information.