For the B command, processing is the same as if you specify Browse Mode from View (option 1), except that mixed mode is the assumed operation mode and you cannot specify a data set format. To browse a data set with mixed mode off, you must use the View option; deselect Mixed Mode and select Browse Mode on the View Entry Panel. If you enter the B line command beside an ISPF library or other partitioned data set, a Browse member list is displayed. For more information about using member selection lists, see the "ISPF Libraries and Data Sets" topic of the z/OS ISPF User's Guide Vol I.