The ornamental design for a foldablehighchair, as shown and described.
FIG. 1 is a perspective rear view of a foldable high chair embodying my new design;
FIG. 2 is a perspective front view thereof;
FIG. 3 is a front elevational view thereof;
FIG. 4 is a rear elevational view thereof;
FIG. 5 is a left side elevational view thereof;
FIG. 6 is a right side elevational view thereof;
FIG. 7 is a top plan view thereof;
FIG. 8 is a bottom plan view thereof;
FIG. 9 is a bottom plan view with hidden detail thereof; and,
FIG. 10 is an unfolded disassembled view thereof.
The broken lines shown in FIG. 9 of the drawings are for illustrative purposes only and form no part of the claimed invention. The dashed lines shown in FIG. 10 are understood to represent fold lines.