The ornamental design for a displayscreen or portion thereof with icon, as shown and described.
FIG. 1 is a front view of a display screen or portion thereof with icon showing our new design; and,
FIG. 2 is an enlarged view thereof, shown separately for clarity of illustration.
The outer perimeter illustrated by a pair of broken lines in FIG. 1 represents a display screen or portion thereof and forms no part of the claimed design. The remaining broken lines in the drawings illustrate portions of the icon that form no part of the claimed design.