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 the 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 the new design for a display screen or a portion thereof with graphical user interface; and,
FIG. 3 is a front view of a third embodiment of the new design for a display screen or a portion thereof with graphical user interface.
The broken line showing of 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 on the display screen illustrates elements of the graphical user interface that form no part of the claimed design.