An ornamentaldesign for a display screen or portion thereof with a computer-generated icon, as shown and described.
The 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.
The FIGURE is a front view of a display screen or portion thereof with a computer-generated icon showing my new design.
The broken lines in the FIGURE illustrate a display screen or portion thereof and form no part of the claimed design.