The ornamental design for a decorative windmillframetop, as shown and described.
FIG. 1 is an upper perspective view of a decorative windmill top showing my new design.
FIG. 2 is a front view thereof, a rear view being identical;
FIG. 3 is a side view thereof, an opposite side view being identical;
FIG. 4 is a top view thereof;
FIG. 5 is a bottom view thereof;
FIG. 6 is a lower perspective view thereof; and,
FIG. 7 is a perspective view illustrating the decorative windmill top in a condition of use.
The broken lines shown in FIGS. 5 and 6 illustrate portions of the decorative windmill frame top that form no part of the claimed design. The broken lines shown in FIG. 7 represent environmental structure that forms no part of the claimed design.