The ornamental design for a displayscreen or portion thereof with a graphicaluserinterface, as shown and described.
FIG. 1 illustrates a front view of an electronic device having a display screen, in accordance with a first embodiment.
FIG. 2 illustrates a front view of an electronic device having a display screen, in accordance with a second embodiment.
FIG. 3 illustrates a front view of an electronic device having a display screen, in accordance with a third embodiment.
FIG. 4 illustrates a front view of an electronic device having a display screen, in accordance with a fourth embodiment.
FIG. 5 illustrates a front view of an electronic device having a display screen, in accordance with a fifth embodiment; and,
FIG. 6 illustrates a front view of an electronic device having a display screen, in accordance with a sixth embodiment.
The outer rectangular broken line in each drawing shows a display screen of an electronic device. The other broken lines showing portions of the graphical user interface form no part of the claimed design.