Display Panel or Portion Thereof with Graphical User Interface

This patent or application file contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawing(s) will be provided by the Office upon request and payment of the necessary fee. FIG. 1 is a front view of a display panel or portion thereof with graphical user interface according to our new design; FIG. 2 is a front view of a second image thereof; FIG. 3 is a front view of a third image thereof; FIG. 4 is a front view of a fourth image thereof; FIG. 5 is a front view of a fifth image thereof; FIG. 6 is a front view of a sixth image thereof; FIG. 7 is a front view of a seventh image thereof; FIG. 8 a front view of an eighth image thereof; FIG. 9 a front view of a ninth image thereof; and, FIG. 10 a front view of a tenth image thereof. The outer dot-dash broken lines show a display panel or portion thereof and boundaries of the claimed design. The interior dot-dash broken lines show boundaries of the claimed design. All the dot-dash broken lines form no part of the claimed design. The appearance of the image transitions sequentially between the images shown in FIGS. 1 - 10 . The process or period in which an image transitions to another forms no part of the claimed design.