Display panel or portion thereof with graphical user interface

[0001]FIG. 1 is a front view of a display panel or portion thereof with graphical user interface showing our new design; and,

[0002]FIG. 2 is a front view thereof shown with environmental matter.

[0003]The dot-dash broken lines forming a rectangle in FIG. 1 illustrate a display panel or portion thereof and form no part of the claimed design. The dash-dash broken lines shown in the graphical user interface represent portions of the graphical user interface that form no part of the claimed design. The additional dot-dash broken lines in FIG. 2 showing a display device illustrate environmental matter that forms no part of the claimed design.