Display Screen or Portion Thereof with a Graphical User Interface

FIG. 1 is a front perspective view of a handheld computing device with a display screen or portion thereof with a graphical user interface showing our new design;

FIG. 2 is a front view thereof;

FIG. 3 is a front view of the handheld computing device with a display screen or portion thereof with a graphical user interface according to a second embodiment thereof; and, FIG. 4 is a front view of the handheld computing device with a display screen or portion thereof with a graphical user interface according to a third embodiment thereof.

Broken lines in FIGS. 1 - 4 show portions of a computing device with the display screen or portion thereof with a graphical user interface and form no part of the claimed design. The oblique lines shown in FIGS. 1 - 4 represent a contrast in appearance and form part of the claimed design.