The ornamental design for a displayscreen or a portion thereof with graphical user interface, as shown and described.
FIG. 1 is a front view of a first embodiment of my new design for a display screen or a portion thereof with graphical user interface;
FIG. 2 is a front view of a second embodiment of my new design for a display screen or a portion thereof with graphical user interface;
FIG. 3 is a front view of a third embodiment of my new design for a display screen or a portion thereof with graphical user interface; and,
FIG. 4 is a front view of a fourth embodiment of my new design for a display screen or a portion thereof with graphical user interface.
The broken line showing of the display and the display screen or a portion thereof is for the purpose of illustrating environment and forms no part of the claimed design. The broken line showing of elements on the display screen illustrate portions of the graphical user interface and form no part of the claimed design.