diff --git a/src/order_gui.cpp b/src/order_gui.cpp
--- a/src/order_gui.cpp
+++ b/src/order_gui.cpp
@@ -435,7 +435,7 @@ private:
 		 * obviously if you press CTRL on a non-empty orders vehicle you know what you are doing */
 		if (this->vehicle->num_orders != 0 && _ctrl_pressed == 0) return false;
 
-		if (DoCommandP(this->vehicle->tile, this->vehicle->index | (u->index << 16), _ctrl_pressed ? CO_SHARE : CO_COPY, NULL,
+		if (DoCommandP(this->vehicle->tile, this->vehicle->index | (u->index << 16), _ctrl_pressed ? CO_SHARE : CO_COPY,
 			_ctrl_pressed ? CMD_CLONE_ORDER | CMD_MSG(STR_CANT_SHARE_ORDER_LIST) : CMD_CLONE_ORDER | CMD_MSG(STR_CANT_COPY_ORDER_LIST))) {
 			this->selected_order = -1;
 			ResetObjectToPlace();
@@ -478,7 +478,7 @@ private:
 		if (load_type < 0) {
 			load_type = order->GetLoadType() == OLF_LOAD_IF_POSSIBLE ? OLF_FULL_LOAD_ANY : OLF_LOAD_IF_POSSIBLE;
 		}
-		DoCommandP(w->vehicle->tile, w->vehicle->index + (sel_ord << 16), MOF_LOAD | (load_type << 4), NULL, CMD_MODIFY_ORDER | CMD_MSG(STR_8835_CAN_T_MODIFY_THIS_ORDER));
+		DoCommandP(w->vehicle->tile, w->vehicle->index + (sel_ord << 16), MOF_LOAD | (load_type << 4), CMD_MODIFY_ORDER | CMD_MSG(STR_8835_CAN_T_MODIFY_THIS_ORDER));
 	}
 
 	/**
@@ -495,7 +495,7 @@ private:
 			if (order == NULL) return;
 			i = (order->GetDepotOrderType() & ODTFB_SERVICE) ? DA_ALWAYS_GO : DA_SERVICE;
 		}
-		DoCommandP(w->vehicle->tile, w->vehicle->index + (sel_ord << 16), MOF_DEPOT_ACTION | (i << 4), NULL, CMD_MODIFY_ORDER | CMD_MSG(STR_8835_CAN_T_MODIFY_THIS_ORDER));
+		DoCommandP(w->vehicle->tile, w->vehicle->index + (sel_ord << 16), MOF_DEPOT_ACTION | (i << 4), CMD_MODIFY_ORDER | CMD_MSG(STR_8835_CAN_T_MODIFY_THIS_ORDER));
 	}
 
 	/**
@@ -511,7 +511,7 @@ private:
 		order.MakeGoToDepot(0, ODTFB_PART_OF_ORDERS);
 		order.SetDepotActionType(ODATFB_NEAREST_DEPOT);
 
-		DoCommandP(w->vehicle->tile, w->vehicle->index + (w->OrderGetSel() << 16), order.Pack(), NULL, CMD_INSERT_ORDER | CMD_MSG(STR_8833_CAN_T_INSERT_NEW_ORDER));
+		DoCommandP(w->vehicle->tile, w->vehicle->index + (w->OrderGetSel() << 16), order.Pack(), CMD_INSERT_ORDER | CMD_MSG(STR_8833_CAN_T_INSERT_NEW_ORDER));
 	}
 
 	/**
@@ -543,7 +543,7 @@ private:
 			unload_type = order->GetUnloadType() == OUF_UNLOAD_IF_POSSIBLE ? OUFB_UNLOAD : OUF_UNLOAD_IF_POSSIBLE;
 		}
 
-		DoCommandP(w->vehicle->tile, w->vehicle->index + (sel_ord << 16), MOF_UNLOAD | (unload_type << 4), NULL, CMD_MODIFY_ORDER | CMD_MSG(STR_8835_CAN_T_MODIFY_THIS_ORDER));
+		DoCommandP(w->vehicle->tile, w->vehicle->index + (sel_ord << 16), MOF_UNLOAD | (unload_type << 4), CMD_MODIFY_ORDER | CMD_MSG(STR_8835_CAN_T_MODIFY_THIS_ORDER));
 	}
 
 	/**
@@ -565,7 +565,7 @@ private:
 		}
 
 		w->InvalidateWidget(ORDER_WIDGET_NON_STOP);
-		DoCommandP(w->vehicle->tile, w->vehicle->index + (sel_ord << 16), MOF_NON_STOP | non_stop << 4,  NULL, CMD_MODIFY_ORDER | CMD_MSG(STR_8835_CAN_T_MODIFY_THIS_ORDER));
+		DoCommandP(w->vehicle->tile, w->vehicle->index + (sel_ord << 16), MOF_NON_STOP | non_stop << 4,  CMD_MODIFY_ORDER | CMD_MSG(STR_8835_CAN_T_MODIFY_THIS_ORDER));
 	}
 
 	/**
@@ -582,7 +582,7 @@ private:
 		if (w->vehicle->num_orders <= 1) return;
 
 		DoCommandP(w->vehicle->tile, w->vehicle->index, _ctrl_pressed ? w->OrderGetSel() : ((w->vehicle->cur_order_index + 1) % w->vehicle->num_orders),
-				NULL, CMD_SKIP_TO_ORDER | CMD_MSG(_ctrl_pressed ? STR_CAN_T_SKIP_TO_ORDER : STR_CAN_T_SKIP_ORDER));
+				CMD_SKIP_TO_ORDER | CMD_MSG(_ctrl_pressed ? STR_CAN_T_SKIP_TO_ORDER : STR_CAN_T_SKIP_ORDER));
 	}
 
 	/**
@@ -595,7 +595,7 @@ private:
 		/* When networking, move one order lower */
 		int selected = w->selected_order + (int)_networking;
 
-		if (DoCommandP(w->vehicle->tile, w->vehicle->index, w->OrderGetSel(), NULL, CMD_DELETE_ORDER | CMD_MSG(STR_8834_CAN_T_DELETE_THIS_ORDER))) {
+		if (DoCommandP(w->vehicle->tile, w->vehicle->index, w->OrderGetSel(), CMD_DELETE_ORDER | CMD_MSG(STR_8834_CAN_T_DELETE_THIS_ORDER))) {
 			w->selected_order = selected >= w->vehicle->num_orders ? -1 : selected;
 		}
 	}
@@ -611,7 +611,7 @@ private:
 	{
 		if (_ctrl_pressed) {
 			/* Cancel refitting */
-			DoCommandP(w->vehicle->tile, w->vehicle->index, (w->OrderGetSel() << 16) | (CT_NO_REFIT << 8) | CT_NO_REFIT, NULL, CMD_ORDER_REFIT);
+			DoCommandP(w->vehicle->tile, w->vehicle->index, (w->OrderGetSel() << 16) | (CT_NO_REFIT << 8) | CT_NO_REFIT, CMD_ORDER_REFIT);
 		} else {
 			ShowVehicleRefitWindow(w->vehicle, w->OrderGetSel(), w);
 		}
@@ -973,7 +973,7 @@ public:
 				default:
 					break;
 			}
-			DoCommandP(this->vehicle->tile, this->vehicle->index + (sel << 16), MOF_COND_VALUE | Clamp(value, 0, 2047) << 4, NULL, CMD_MODIFY_ORDER | CMD_MSG(STR_8835_CAN_T_MODIFY_THIS_ORDER));
+			DoCommandP(this->vehicle->tile, this->vehicle->index + (sel << 16), MOF_COND_VALUE | Clamp(value, 0, 2047) << 4, CMD_MODIFY_ORDER | CMD_MSG(STR_8835_CAN_T_MODIFY_THIS_ORDER));
 		}
 	}
 
@@ -1006,11 +1006,11 @@ public:
 				break;
 
 			case ORDER_WIDGET_COND_VARIABLE:
-				DoCommandP(this->vehicle->tile, this->vehicle->index + (this->OrderGetSel() << 16), MOF_COND_VARIABLE | index << 4,  NULL, CMD_MODIFY_ORDER | CMD_MSG(STR_8835_CAN_T_MODIFY_THIS_ORDER));
+				DoCommandP(this->vehicle->tile, this->vehicle->index + (this->OrderGetSel() << 16), MOF_COND_VARIABLE | index << 4,  CMD_MODIFY_ORDER | CMD_MSG(STR_8835_CAN_T_MODIFY_THIS_ORDER));
 				break;
 
 			case ORDER_WIDGET_COND_COMPARATOR:
-				DoCommandP(this->vehicle->tile, this->vehicle->index + (this->OrderGetSel() << 16), MOF_COND_COMPARATOR | index << 4,  NULL, CMD_MODIFY_ORDER | CMD_MSG(STR_8835_CAN_T_MODIFY_THIS_ORDER));
+				DoCommandP(this->vehicle->tile, this->vehicle->index + (this->OrderGetSel() << 16), MOF_COND_COMPARATOR | index << 4,  CMD_MODIFY_ORDER | CMD_MSG(STR_8835_CAN_T_MODIFY_THIS_ORDER));
 				break;
 		}
 	}
@@ -1023,7 +1023,7 @@ public:
 				int to_order = this->GetOrderFromPt(pt.y);
 
 				if (!(from_order == to_order || from_order == INVALID_ORDER || from_order > this->vehicle->num_orders || to_order == INVALID_ORDER || to_order > this->vehicle->num_orders) &&
-						DoCommandP(this->vehicle->tile, this->vehicle->index, from_order | (to_order << 16), NULL, CMD_MOVE_ORDER | CMD_MSG(STR_CAN_T_MOVE_THIS_ORDER))) {
+						DoCommandP(this->vehicle->tile, this->vehicle->index, from_order | (to_order << 16), CMD_MOVE_ORDER | CMD_MSG(STR_CAN_T_MOVE_THIS_ORDER))) {
 					this->selected_order = -1;
 				}
 			} break;
@@ -1069,7 +1069,7 @@ public:
 			const Order cmd = GetOrderCmdFromTile(this->vehicle, tile);
 			if (!cmd.IsValid()) return;
 
-			if (DoCommandP(this->vehicle->tile, this->vehicle->index + (this->OrderGetSel() << 16), cmd.Pack(), NULL, CMD_INSERT_ORDER | CMD_MSG(STR_8833_CAN_T_INSERT_NEW_ORDER))) {
+			if (DoCommandP(this->vehicle->tile, this->vehicle->index + (this->OrderGetSel() << 16), cmd.Pack(), CMD_INSERT_ORDER | CMD_MSG(STR_8833_CAN_T_INSERT_NEW_ORDER))) {
 				ResetObjectToPlace();
 			}
 		}
@@ -1090,7 +1090,7 @@ public:
 					order.index = 0;
 					order.MakeConditional(order_id);
 
-					DoCommandP(this->vehicle->tile, this->vehicle->index + (this->OrderGetSel() << 16), order.Pack(), NULL, CMD_INSERT_ORDER | CMD_MSG(STR_8833_CAN_T_INSERT_NEW_ORDER));
+					DoCommandP(this->vehicle->tile, this->vehicle->index + (this->OrderGetSel() << 16), order.Pack(), CMD_INSERT_ORDER | CMD_MSG(STR_8833_CAN_T_INSERT_NEW_ORDER));
 				}
 			}
 		}