An operating unit has an operating program and a touch-sensitive display screen on which display fields and/or navigation fields can be represented. Upon actuation of the operating fields, operating signals can be sent by a control or regulating device to injection molding machine elements. Upon actuation of the navigation fields, pages of the operating program can be called up. At least one operating group contains the operating fields but no navigation fields, and/or navigation groups contain the navigation fields but no operating fields. At least one passive field in the form of rows and/or columns contains neither operating fields nor navigational fields. The least one operating group and/or the navigation groups are arranged in rows and/or columns, and the at least one passive field is arranged between the navigation groups and/or the at least one operating group.