rem: (*panel->action)(panel->action, panel->clientData);
add: (*panel->action)(panel, panel->clientData);
context: wheelHandleActionEvents(XEvent *event, void *data){    W_ColorPanel	*panel = (W_ColorPanel*)data;        switch (event->type) {     case ButtonPress:	if (getPickerPart(panel, event->xbutton.x, event->xbutton.y) == 	    COLORWHEEL_PART) {	    panel->flags.dragging = 1;	    wheelPositionSelection(panel, event->xbutton.x, 				   event->xbutton.y);	}	break;	     case ButtonRelease:	panel->flags.dragging = 0;	if (!panel->flags.continuous) {	    if (panel->action)		(*panel->action)(panel->action, panel->clientData);	}	break;	     case MotionNotify:	if (panel->flags.dragging) {	    if (getPickerPart(panel, event->xmotion.x, event->xmotion.y) ==		COLORWHEEL_PART) {		wheelPositionSelection(panel, event->xmotion.x, 				       event->xmotion.y);	    }	    else		wheelPositionSelectionOutBounds(panel, event->xmotion.x, 						event->xmotion.y);	}	break;    }}