The ornamental design for a displayscreen or portion thereof with transitional graphical user interface, as shown and described.
FIG. 1 is a front view of a display screen or portion thereof with transitional graphical user interface showing a first image in a sequence, showing our new design;
FIG. 2 is a front view showing a second image thereof;
FIG. 3 is a front view showing a third image thereof;
FIG. 4 is a front view showing a fourth image thereof;
FIG. 5 is a front view showing a fifth image thereof;
FIG. 6 is a front view showing a sixth image thereof;
FIG. 7 is a front view showing a seventh image thereof; and,
FIG. 8 is a front view showing an eighth image thereof.
The outermost perimeter shown in broken lines represents display screens or portions thereof and forms no part of the claimed design.
The appearance of the transitional graphical user interface sequentially transitions between the images shown in FIGS. 1-8. The process or period in which one image transitions to another image forms no part of the claimed design.
The solid black shading shown in the figures represents a contrast of appearance.