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 outer perimeter shown in broken lines in the drawings represents a display screen or portion 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 contrast shown in grayscale in the figures represents a contrast of appearance.