The ornamental design for a windowtreatmenttemplatedesign, substantially as shown in the attached drawings.
FIG. 1 is a top view of the window treatment template design, wherein the large cut-outs of the template represent windows on a building wall and the thin cut-outs of the template represent trim that may exist around the windows;
FIG. 2 is a right side view of the window treatment template design;
FIG. 3 is a left side view of the window treatment template design;
FIG. 4 is a bottom view of the window treatment template design;
FIG. 5 is a perspective view of the window treatment template design;
FIG. 6 is a front view of the window treatment template design; and,
FIG. 7 is a back view of the window treatment template design.