The ornamental design for a portion of a shoe upper, as shown and described.
FIG. 1 is a side elevational view of a portion of a shoe upper showing my new design;
FIG. 2 is a first perspective view thereof;
FIG. 3 is a second perspective view thereof; and,
FIG. 4 is a top plan view thereof.
The uneven broken line immediately adjacent to the shaded area represents an unclaimed boundary of the design. The uneven broken line showing of the remainder of the shoe is for illustrative purposes only and forms no part of the claimed design.