A method and apparatus is disclosed for operating a medical device with a screen having an improved graphical user interface, which selectively reallocates screen display for both single and multi-channel pumps. Channel indicators associate operation information with a specific delivery channel. Patient or drug order verification is facilitated with a rendering of the patient or the entire drug order/label on the screen. Decimal numbers are presented in vertically offset decimal format. A dual function button cancels the current operation and, after a delay, clears entered parameters. An area sensitive scrollbar cycles through information at various speeds. Screen brightness is adjusted based on an ambient light detector. A screen saver mode activates based on several operating conditions. The screen is incorporated in a removable user interface.