Display Panel or Portion Thereof with a Computer-generated Graphical User Interface

The FIGURE is a front view of a display panel or portion thereof with a computer-generated graphical user interface.

The dashed lines represent environmental subject matter forming no part of the claimed design. The dot-dash lines in the FIGURE represent a boundary of the claimed design on a display panel or portion thereof forming no part of the claimed design. Further, the dimensions of the display panel relative to the user interface depicted thereon are not drawn to any specific scale.

The dot-dash broken lines show the display panel or portion thereof and the boundary of the claimed design and form no part of the claimed design. The remaining broken lines show portions of the computer-generated graphical user interface and form no part of the claimed design.