Display Panel or Portion Thereof with a Computer Icon

FIG. 1 is a front perspective view of a handheld computing device having a display panel or portion thereof with a computer icon and shows a first image of the new design; FIG. 2 is a front view of the first image in a sequence showing the display panel or portion thereof with the computer icon; and, FIG. 3 is a second image in the sequence thereof. The design sequentially transitions between the images shown in FIGS. 2 - 3 . The process or period in which one image transitions to another image forms no part of the claimed design. Broken lines in FIGS. 1 - 3 show portions of a computing device with the display panel and form no part of the claimed design.