diff --git a/src/timetable_gui.cpp b/src/timetable_gui.cpp
--- a/src/timetable_gui.cpp
+++ b/src/timetable_gui.cpp
@@ -294,18 +294,18 @@ struct TimetableWindow : Window {
 
 			case TTV_CLEAR_TIME: { /* Clear waiting time button. */
 				uint32 p1 = PackTimetableArgs(v, this->sel_index);
-				DoCommandP(0, p1, 0, NULL, CMD_CHANGE_TIMETABLE | CMD_MSG(STR_CAN_T_TIMETABLE_VEHICLE));
+				DoCommandP(0, p1, 0, CMD_CHANGE_TIMETABLE | CMD_MSG(STR_CAN_T_TIMETABLE_VEHICLE));
 			} break;
 
 			case TTV_RESET_LATENESS: /* Reset the vehicle's late counter. */
-				DoCommandP(0, v->index, 0, NULL, CMD_SET_VEHICLE_ON_TIME | CMD_MSG(STR_CAN_T_TIMETABLE_VEHICLE));
+				DoCommandP(0, v->index, 0, CMD_SET_VEHICLE_ON_TIME | CMD_MSG(STR_CAN_T_TIMETABLE_VEHICLE));
 				break;
 
 			case TTV_AUTOFILL: { /* Autofill the timetable. */
 				uint32 p2 = 0;
 				if (!HasBit(v->vehicle_flags, VF_AUTOFILL_TIMETABLE)) SetBit(p2, 0);
 				if (_ctrl_pressed) SetBit(p2, 1);
-				DoCommandP(0, v->index, p2, NULL, CMD_AUTOFILL_TIMETABLE | CMD_MSG(STR_CAN_T_TIMETABLE_VEHICLE));
+				DoCommandP(0, v->index, p2, CMD_AUTOFILL_TIMETABLE | CMD_MSG(STR_CAN_T_TIMETABLE_VEHICLE));
 			} break;
 		}
 
@@ -325,7 +325,7 @@ struct TimetableWindow : Window {
 
 		uint32 p2 = minu(time, UINT16_MAX);
 
-		DoCommandP(0, p1, p2, NULL, CMD_CHANGE_TIMETABLE | CMD_MSG(STR_CAN_T_TIMETABLE_VEHICLE));
+		DoCommandP(0, p1, p2, CMD_CHANGE_TIMETABLE | CMD_MSG(STR_CAN_T_TIMETABLE_VEHICLE));
 	}
 
 	virtual void OnResize(Point new_size, Point delta)