The ornamental design for a controlpanel, as shown and described.
FIG. 1 is a perspective view of a control panel;
FIG. 2 is a front view thereof;
FIG. 3 is a back view thereof;
FIG. 4 is a left view thereof;
FIG. 5 is a right view thereof;
FIG. 6 is a top view thereof;
FIG. 7 is a bottom view thereof; and,
FIG. 8 is a perspective view thereof showing an example in use; wherein the broken lines are shown for illustrative purpose only and from no part of the claimed design.