The ornamental design for a computerscreendisplay or portion thereof with graphical user interface, as shown and described.
The FIGURE is a front view of a computer screen display or potion thereof with graphical user interface showing the new design.
The outermost broken line illustrates the computer screen display, and the broken line showing of alpha-numeric text within the outermost broken :line illustrate portions of the graphical user interface, None of the broken lines form part of the claimed design.