diff --git a/src/airport_gui.cpp b/src/airport_gui.cpp
--- a/src/airport_gui.cpp
+++ b/src/airport_gui.cpp
@@ -39,7 +39,7 @@ static void PlaceAirport(TileIndex tile)
 
 static void PlaceAir_DemolishArea(TileIndex tile)
 {
-	VpStartPlaceSizing(tile, 4);
+	VpStartPlaceSizing(tile, VPM_X_AND_Y, GUI_PlaceProc_None);
 }
 
 
@@ -91,7 +91,7 @@ static void BuildAirToolbWndProc(Window 
 		break;
 
 	case WE_PLACE_DRAG:
-		VpSelectTilesWithMethod(e->we.place.pt.x, e->we.place.pt.y, e->we.place.userdata);
+		VpSelectTilesWithMethod(e->we.place.pt.x, e->we.place.pt.y, e->we.place.select_method);
 		break;
 
 	case WE_PLACE_MOUSEUP:
diff --git a/src/dock_gui.cpp b/src/dock_gui.cpp
--- a/src/dock_gui.cpp
+++ b/src/dock_gui.cpp
@@ -53,12 +53,12 @@ static void PlaceDocks_Buoy(TileIndex ti
 
 static void PlaceDocks_DemolishArea(TileIndex tile)
 {
-	VpStartPlaceSizing(tile, VPM_X_AND_Y | GUI_PlaceProc_DemolishArea);
+	VpStartPlaceSizing(tile, VPM_X_AND_Y, GUI_PlaceProc_DemolishArea);
 }
 
 static void PlaceDocks_BuildCanal(TileIndex tile)
 {
-	VpStartPlaceSizing(tile, VPM_X_OR_Y);
+	VpStartPlaceSizing(tile, VPM_X_OR_Y, GUI_PlaceProc_None);
 }
 
 static void PlaceDocks_BuildLock(TileIndex tile)
@@ -147,16 +147,20 @@ static void BuildDocksToolbWndProc(Windo
 		break;
 
 	case WE_PLACE_DRAG: {
-		VpSelectTilesWithMethod(e->we.place.pt.x, e->we.place.pt.y, e->we.place.userdata);
+		VpSelectTilesWithMethod(e->we.place.pt.x, e->we.place.pt.y, e->we.place.select_method);
 		return;
 	}
 
 	case WE_PLACE_MOUSEUP:
 		if (e->we.place.pt.x != -1) {
-			if ((e->we.place.userdata & 0xF) == VPM_X_AND_Y) { // dragged actions
-				GUIPlaceProcDragXY(e);
-			} else if (e->we.place.userdata == VPM_X_OR_Y) {
-				DoCommandP(e->we.place.tile, e->we.place.starttile, 0, CcBuildCanal, CMD_BUILD_CANAL | CMD_AUTO | CMD_MSG(STR_CANT_BUILD_CANALS));
+			switch (e->we.place.select_method) {
+				case VPM_X_AND_Y:
+					GUIPlaceProcDragXY(e);
+					break;
+				case VPM_X_OR_Y:
+					DoCommandP(e->we.place.tile, e->we.place.starttile, 0, CcBuildCanal, CMD_BUILD_CANAL | CMD_AUTO | CMD_MSG(STR_CANT_BUILD_CANALS));
+					break;
+				default: break;
 			}
 		}
 		break;
diff --git a/src/gui.h b/src/gui.h
--- a/src/gui.h
+++ b/src/gui.h
@@ -68,14 +68,15 @@ void PlaceProc_DemolishArea(TileIndex ti
 void PlaceProc_LevelLand(TileIndex tile);
 bool GUIPlaceProcDragXY(const WindowEvent *e);
 
-enum { // max 32 - 4 = 28 types
-	GUI_PlaceProc_DemolishArea    = 0 << 4,
-	GUI_PlaceProc_LevelArea       = 1 << 4,
-	GUI_PlaceProc_DesertArea      = 2 << 4,
-	GUI_PlaceProc_WaterArea       = 3 << 4,
-	GUI_PlaceProc_ConvertRailArea = 4 << 4,
-	GUI_PlaceProc_RockyArea       = 5 << 4,
-	GUI_PlaceProc_RemoveFromStation = 6 << 4,
+enum {
+	GUI_PlaceProc_None,
+	GUI_PlaceProc_DemolishArea,
+	GUI_PlaceProc_LevelArea,
+	GUI_PlaceProc_DesertArea,
+	GUI_PlaceProc_WaterArea,
+	GUI_PlaceProc_ConvertRailArea,
+	GUI_PlaceProc_RockyArea,
+	GUI_PlaceProc_RemoveFromStation,
 };
 
 /* misc_gui.cpp */
diff --git a/src/main_gui.cpp b/src/main_gui.cpp
--- a/src/main_gui.cpp
+++ b/src/main_gui.cpp
@@ -1131,7 +1131,7 @@ static void PlaceProc_LowerBigLand(TileI
 
 static void PlaceProc_RockyArea(TileIndex tile)
 {
-	VpStartPlaceSizing(tile, VPM_X_AND_Y | GUI_PlaceProc_RockyArea);
+	VpStartPlaceSizing(tile, VPM_X_AND_Y, GUI_PlaceProc_RockyArea);
 }
 
 static void PlaceProc_LightHouse(TileIndex tile)
@@ -1158,12 +1158,12 @@ static void PlaceProc_Transmitter(TileIn
 
 static void PlaceProc_DesertArea(TileIndex tile)
 {
-	VpStartPlaceSizing(tile, VPM_X_AND_Y | GUI_PlaceProc_DesertArea);
+	VpStartPlaceSizing(tile, VPM_X_AND_Y, GUI_PlaceProc_DesertArea);
 }
 
 static void PlaceProc_WaterArea(TileIndex tile)
 {
-	VpStartPlaceSizing(tile, VPM_X_AND_Y | GUI_PlaceProc_WaterArea);
+	VpStartPlaceSizing(tile, VPM_X_AND_Y, GUI_PlaceProc_WaterArea);
 }
 
 static const Widget _scen_edit_land_gen_widgets[] = {
@@ -1377,12 +1377,12 @@ static void ScenEditLandGenWndProc(Windo
 		_place_proc(e->we.place.tile);
 		break;
 	case WE_PLACE_DRAG:
-		VpSelectTilesWithMethod(e->we.place.pt.x, e->we.place.pt.y, e->we.place.userdata & 0xF);
+		VpSelectTilesWithMethod(e->we.place.pt.x, e->we.place.pt.y, e->we.place.select_method);
 		break;
 
 	case WE_PLACE_MOUSEUP:
 		if (e->we.place.pt.x != -1) {
-			if ((e->we.place.userdata & 0xF) == VPM_X_AND_Y) // dragged actions
+			if (e->we.place.select_method == VPM_X_AND_Y) // dragged actions
 				GUIPlaceProcDragXY(e);
 		}
 		break;
diff --git a/src/misc_gui.cpp b/src/misc_gui.cpp
--- a/src/misc_gui.cpp
+++ b/src/misc_gui.cpp
@@ -382,12 +382,12 @@ static void BuildTreesWndProc(Window *w,
 	} break;
 
 	case WE_PLACE_OBJ:
-		VpStartPlaceSizing(e->we.place.tile, VPM_X_AND_Y_LIMITED);
+		VpStartPlaceSizing(e->we.place.tile, VPM_X_AND_Y_LIMITED, GUI_PlaceProc_None);
 		VpSetPlaceSizingLimit(20);
 		break;
 
 	case WE_PLACE_DRAG:
-		VpSelectTilesWithMethod(e->we.place.pt.x, e->we.place.pt.y, e->we.place.userdata);
+		VpSelectTilesWithMethod(e->we.place.pt.x, e->we.place.pt.y, e->we.place.select_method);
 		return;
 
 	case WE_PLACE_MOUSEUP:
diff --git a/src/rail_gui.cpp b/src/rail_gui.cpp
--- a/src/rail_gui.cpp
+++ b/src/rail_gui.cpp
@@ -72,7 +72,7 @@ static void PlaceRail_N(TileIndex tile)
 
 static void PlaceRail_NE(TileIndex tile)
 {
-	VpStartPlaceSizing(tile, VPM_FIX_Y);
+	VpStartPlaceSizing(tile, VPM_FIX_Y, GUI_PlaceProc_None);
 }
 
 static void PlaceRail_E(TileIndex tile)
@@ -83,12 +83,12 @@ static void PlaceRail_E(TileIndex tile)
 
 static void PlaceRail_NW(TileIndex tile)
 {
-	VpStartPlaceSizing(tile, VPM_FIX_X);
+	VpStartPlaceSizing(tile, VPM_FIX_X, GUI_PlaceProc_None);
 }
 
 static void PlaceRail_AutoRail(TileIndex tile)
 {
-	VpStartPlaceSizing(tile, VPM_RAILDIRS);
+	VpStartPlaceSizing(tile, VPM_RAILDIRS, GUI_PlaceProc_None);
 }
 
 static void PlaceExtraDepotRail(TileIndex tile, uint16 extra)
@@ -151,9 +151,9 @@ void CcStation(bool success, TileIndex t
 static void PlaceRail_Station(TileIndex tile)
 {
 	if (_remove_button_clicked) {
-		VpStartPlaceSizing(tile, VPM_X_AND_Y | GUI_PlaceProc_RemoveFromStation);
+		VpStartPlaceSizing(tile, VPM_X_AND_Y, GUI_PlaceProc_RemoveFromStation);
 	} else if (_railstation.dragdrop) {
-		VpStartPlaceSizing(tile, VPM_X_AND_Y_LIMITED);
+		VpStartPlaceSizing(tile, VPM_X_AND_Y_LIMITED, GUI_PlaceProc_None);
 		VpSetPlaceSizingLimit(_patches.station_spread);
 	} else {
 		DoCommandP(tile,
@@ -197,7 +197,7 @@ static void GenericPlaceSignals(TileInde
 
 static void PlaceRail_Bridge(TileIndex tile)
 {
-	VpStartPlaceSizing(tile, VPM_X_OR_Y);
+	VpStartPlaceSizing(tile, VPM_X_OR_Y, GUI_PlaceProc_None);
 }
 
 void CcBuildRailTunnel(bool success, TileIndex tile, uint32 p1, uint32 p2)
@@ -223,12 +223,12 @@ void PlaceProc_BuyLand(TileIndex tile)
 
 static void PlaceRail_ConvertRail(TileIndex tile)
 {
-	VpStartPlaceSizing(tile, VPM_X_AND_Y | GUI_PlaceProc_ConvertRailArea);
+	VpStartPlaceSizing(tile, VPM_X_AND_Y, GUI_PlaceProc_ConvertRailArea);
 }
 
 static void PlaceRail_AutoSignals(TileIndex tile)
 {
-	VpStartPlaceSizing(tile, VPM_SIGNALDIRS);
+	VpStartPlaceSizing(tile, VPM_SIGNALDIRS, GUI_PlaceProc_None);
 }
 
 
@@ -492,7 +492,7 @@ static void BuildRailToolbWndProc(Window
 		return;
 
 	case WE_PLACE_DRAG: {
-		VpSelectTilesWithMethod(e->we.place.pt.x, e->we.place.pt.y, e->we.place.userdata & 0xF);
+		VpSelectTilesWithMethod(e->we.place.pt.x, e->we.place.pt.y, e->we.place.select_method);
 		return;
 	}
 
@@ -501,30 +501,45 @@ static void BuildRailToolbWndProc(Window
 			TileIndex start_tile = e->we.place.starttile;
 			TileIndex end_tile = e->we.place.tile;
 
-			if (e->we.place.userdata == VPM_X_OR_Y) {
-				ResetObjectToPlace();
-				ShowBuildBridgeWindow(start_tile, end_tile, _cur_railtype);
-			} else if (e->we.place.userdata == VPM_RAILDIRS) {
-				bool old = _remove_button_clicked;
-				if (_ctrl_pressed) _remove_button_clicked = true;
-				HandleAutodirPlacement();
-				_remove_button_clicked = old;
-			} else if (e->we.place.userdata == VPM_SIGNALDIRS) {
-				HandleAutoSignalPlacement();
-			} else if ((e->we.place.userdata & 0xF) == VPM_X_AND_Y) {
-				if (GUIPlaceProcDragXY(e)) break;
+			switch (e->we.place.select_method) {
+				case VPM_X_OR_Y:
+					ResetObjectToPlace();
+					ShowBuildBridgeWindow(start_tile, end_tile, _cur_railtype);
+					break;
 
-				if ((e->we.place.userdata >> 4) == GUI_PlaceProc_RemoveFromStation >> 4) {
-					DoCommandP(end_tile, start_tile, 0, CcPlaySound1E, CMD_REMOVE_FROM_RAILROAD_STATION | CMD_MSG(STR_CANT_REMOVE_PART_OF_STATION));
+				case VPM_RAILDIRS: {
+					bool old = _remove_button_clicked;
+					if (_ctrl_pressed) _remove_button_clicked = true;
+					HandleAutodirPlacement();
+					_remove_button_clicked = old;
+					break;
 				}
 
-				if ((e->we.place.userdata >> 4) == GUI_PlaceProc_ConvertRailArea >> 4) {
-					DoCommandP(end_tile, start_tile, _cur_railtype, CcPlaySound10, CMD_CONVERT_RAIL | CMD_MSG(STR_CANT_CONVERT_RAIL));
-				}
-			} else if (e->we.place.userdata == VPM_X_AND_Y_LIMITED) {
-				HandleStationPlacement(start_tile, end_tile);
-			} else {
-				DoRailroadTrack(e->we.place.userdata & 1);
+				case VPM_SIGNALDIRS:
+					HandleAutoSignalPlacement();
+					break;
+
+				case VPM_X_AND_Y:
+					if (GUIPlaceProcDragXY(e)) break;
+
+					switch (e->we.place.select_proc) {
+						case GUI_PlaceProc_RemoveFromStation:
+							DoCommandP(end_tile, start_tile, 0, CcPlaySound1E, CMD_REMOVE_FROM_RAILROAD_STATION | CMD_MSG(STR_CANT_REMOVE_PART_OF_STATION));
+							break;
+
+						case GUI_PlaceProc_ConvertRailArea:
+							DoCommandP(end_tile, start_tile, _cur_railtype, CcPlaySound10, CMD_CONVERT_RAIL | CMD_MSG(STR_CANT_CONVERT_RAIL));
+							break;
+					}
+					break;
+
+				case VPM_X_AND_Y_LIMITED:
+					HandleStationPlacement(start_tile, end_tile);
+					break;
+
+				default:
+					DoRailroadTrack(e->we.place.select_method == VPM_FIX_Y ? TRACK_X : TRACK_Y);
+					break;
 			}
 		}
 		break;
diff --git a/src/road_gui.cpp b/src/road_gui.cpp
--- a/src/road_gui.cpp
+++ b/src/road_gui.cpp
@@ -45,18 +45,18 @@ void CcPlaySound1D(bool success, TileInd
 static void PlaceRoad_NE(TileIndex tile)
 {
 	_place_road_flag = (_tile_fract_coords.y >= 8) + 4;
-	VpStartPlaceSizing(tile, VPM_FIX_X);
+	VpStartPlaceSizing(tile, VPM_FIX_X, GUI_PlaceProc_None);
 }
 
 static void PlaceRoad_NW(TileIndex tile)
 {
 	_place_road_flag = (_tile_fract_coords.x >= 8) + 0;
-	VpStartPlaceSizing(tile, VPM_FIX_Y);
+	VpStartPlaceSizing(tile, VPM_FIX_Y, GUI_PlaceProc_None);
 }
 
 static void PlaceRoad_Bridge(TileIndex tile)
 {
-	VpStartPlaceSizing(tile, VPM_X_OR_Y);
+	VpStartPlaceSizing(tile, VPM_X_OR_Y, GUI_PlaceProc_None);
 }
 
 
@@ -134,7 +134,7 @@ static void PlaceRoad_TruckStation(TileI
 
 static void PlaceRoad_DemolishArea(TileIndex tile)
 {
-	VpStartPlaceSizing(tile, 4);
+	VpStartPlaceSizing(tile, VPM_X_AND_Y, GUI_PlaceProc_None);
 }
 
 
@@ -270,47 +270,41 @@ static void BuildRoadToolbWndProc(Window
 		if (w != NULL) WP(w, def_d).close = true;
 		break;
 
-	case WE_PLACE_DRAG: {
-		int sel_method;
-		switch (e->we.place.userdata) {
-			case 1:
-				sel_method = VPM_FIX_X;
+	case WE_PLACE_DRAG:
+		switch (e->we.place.select_method) {
+			case VPM_FIX_X:
 				_place_road_flag = (_place_road_flag & ~2) | ((e->we.place.pt.y & 8) >> 2);
 				break;
 
-			case 2:
-				sel_method = VPM_FIX_Y;
+			case VPM_FIX_Y:
 				_place_road_flag = (_place_road_flag & ~2) | ((e->we.place.pt.x & 8) >> 2);
 				break;
-
-			case 4:
-				sel_method = VPM_X_AND_Y;
-				break;
-
-			default:
-				sel_method = VPM_X_OR_Y;
-				break;
 		}
 
-		VpSelectTilesWithMethod(e->we.place.pt.x, e->we.place.pt.y, sel_method);
+		VpSelectTilesWithMethod(e->we.place.pt.x, e->we.place.pt.y, e->we.place.select_method);
 		return;
-	}
 
 	case WE_PLACE_MOUSEUP:
 		if (e->we.place.pt.x != -1) {
 			TileIndex start_tile = e->we.place.starttile;
 			TileIndex end_tile = e->we.place.tile;
 
-			if (e->we.place.userdata == 0) {
-				ResetObjectToPlace();
-				ShowBuildBridgeWindow(start_tile, end_tile, 0x80 | RoadTypeToRoadTypes(_cur_roadtype));
-			} else if (e->we.place.userdata != 4) {
-				DoCommandP(end_tile, start_tile, _place_road_flag | (_cur_roadtype << 3), CcPlaySound1D,
-					_remove_button_clicked ?
-					CMD_REMOVE_LONG_ROAD | CMD_AUTO | CMD_NO_WATER | CMD_MSG(STR_1805_CAN_T_REMOVE_ROAD_FROM) :
-					CMD_BUILD_LONG_ROAD | CMD_AUTO | CMD_NO_WATER | CMD_MSG(STR_1804_CAN_T_BUILD_ROAD_HERE));
-			} else {
-				DoCommandP(end_tile, start_tile, 0, CcPlaySound10, CMD_CLEAR_AREA | CMD_MSG(STR_00B5_CAN_T_CLEAR_THIS_AREA));
+			switch (e->we.place.select_method) {
+				case VPM_X_OR_Y:
+					ResetObjectToPlace();
+					ShowBuildBridgeWindow(start_tile, end_tile, 0x80 | RoadTypeToRoadTypes(_cur_roadtype));
+					break;
+
+				case VPM_X_AND_Y:
+					DoCommandP(end_tile, start_tile, 0, CcPlaySound10, CMD_CLEAR_AREA | CMD_MSG(STR_00B5_CAN_T_CLEAR_THIS_AREA));
+					break;
+
+				default:
+					DoCommandP(end_tile, start_tile, _place_road_flag | (_cur_roadtype << 3), CcPlaySound1D,
+						_remove_button_clicked ?
+						CMD_REMOVE_LONG_ROAD | CMD_AUTO | CMD_NO_WATER | CMD_MSG(STR_1805_CAN_T_REMOVE_ROAD_FROM) :
+						CMD_BUILD_LONG_ROAD | CMD_AUTO | CMD_NO_WATER | CMD_MSG(STR_1804_CAN_T_BUILD_ROAD_HERE));
+					break;
 			}
 		}
 		break;
diff --git a/src/terraform_gui.cpp b/src/terraform_gui.cpp
--- a/src/terraform_gui.cpp
+++ b/src/terraform_gui.cpp
@@ -104,23 +104,24 @@ bool GUIPlaceProcDragXY(const WindowEven
 	TileIndex start_tile = e->we.place.starttile;
 	TileIndex end_tile = e->we.place.tile;
 
-	switch (e->we.place.userdata >> 4) {
-	case GUI_PlaceProc_DemolishArea >> 4:
-		DoCommandP(end_tile, start_tile, 0, CcPlaySound10, CMD_CLEAR_AREA | CMD_MSG(STR_00B5_CAN_T_CLEAR_THIS_AREA));
-		break;
-	case GUI_PlaceProc_LevelArea >> 4:
-		DoCommandP(end_tile, start_tile, 0, CcPlaySound10, CMD_LEVEL_LAND | CMD_AUTO);
-		break;
-	case GUI_PlaceProc_RockyArea >> 4:
-		GenerateRockyArea(end_tile, start_tile);
-		break;
-	case GUI_PlaceProc_DesertArea >> 4:
-		GenerateDesertArea(end_tile, start_tile);
-		break;
-	case GUI_PlaceProc_WaterArea >> 4:
-		DoCommandP(end_tile, start_tile, _ctrl_pressed, CcBuildCanal, CMD_BUILD_CANAL | CMD_AUTO | CMD_MSG(STR_CANT_BUILD_CANALS));
-		break;
-	default: return false;
+	switch (e->we.place.select_proc) {
+		case GUI_PlaceProc_DemolishArea:
+			DoCommandP(end_tile, start_tile, 0, CcPlaySound10, CMD_CLEAR_AREA | CMD_MSG(STR_00B5_CAN_T_CLEAR_THIS_AREA));
+			break;
+		case GUI_PlaceProc_LevelArea:
+			DoCommandP(end_tile, start_tile, 0, CcPlaySound10, CMD_LEVEL_LAND | CMD_AUTO);
+			break;
+		case GUI_PlaceProc_RockyArea:
+			GenerateRockyArea(end_tile, start_tile);
+			break;
+		case GUI_PlaceProc_DesertArea:
+			GenerateDesertArea(end_tile, start_tile);
+			break;
+		case GUI_PlaceProc_WaterArea:
+			DoCommandP(end_tile, start_tile, _ctrl_pressed, CcBuildCanal, CMD_BUILD_CANAL | CMD_AUTO | CMD_MSG(STR_CANT_BUILD_CANALS));
+			break;
+		default:
+			return false;
 	}
 
 	return true;
@@ -140,7 +141,7 @@ static const uint16 _terraform_keycodes[
 
 void PlaceProc_DemolishArea(TileIndex tile)
 {
-	VpStartPlaceSizing(tile, VPM_X_AND_Y | GUI_PlaceProc_DemolishArea);
+	VpStartPlaceSizing(tile, VPM_X_AND_Y, GUI_PlaceProc_DemolishArea);
 }
 
 static void PlaceProc_RaiseLand(TileIndex tile)
@@ -161,7 +162,7 @@ static void PlaceProc_LowerLand(TileInde
 
 void PlaceProc_LevelLand(TileIndex tile)
 {
-	VpStartPlaceSizing(tile, VPM_X_AND_Y | GUI_PlaceProc_LevelArea);
+	VpStartPlaceSizing(tile, VPM_X_AND_Y, GUI_PlaceProc_LevelArea);
 }
 
 static void TerraformClick_Lower(Window *w)
@@ -239,12 +240,11 @@ static void TerraformToolbWndProc(Window
 		return;
 
 	case WE_PLACE_DRAG:
-		VpSelectTilesWithMethod(e->we.place.pt.x, e->we.place.pt.y, e->we.place.userdata & 0xF);
+		VpSelectTilesWithMethod(e->we.place.pt.x, e->we.place.pt.y, e->we.place.select_method);
 		break;
 
 	case WE_PLACE_MOUSEUP:
-		if (e->we.place.pt.x != -1 &&
-				(e->we.place.userdata & 0xF) == VPM_X_AND_Y) { // dragged actions
+		if (e->we.place.pt.x != -1 && e->we.place.select_method == VPM_X_AND_Y) {
 			GUIPlaceProcDragXY(e);
 		}
 		break;
diff --git a/src/viewport.cpp b/src/viewport.cpp
--- a/src/viewport.cpp
+++ b/src/viewport.cpp
@@ -1985,9 +1985,10 @@ void UpdateTileSelection()
 }
 
 /** highlighting tiles while only going over them with the mouse */
-void VpStartPlaceSizing(TileIndex tile, int user)
+void VpStartPlaceSizing(TileIndex tile, byte method, byte process)
 {
-	_thd.userdata = user;
+	_thd.select_method = method;
+	_thd.select_proc   = process;
 	_thd.selend.x = TileX(tile) * TILE_SIZE;
 	_thd.selstart.x = TileX(tile) * TILE_SIZE;
 	_thd.selend.y = TileY(tile) * TILE_SIZE;
@@ -2445,7 +2446,8 @@ bool VpHandlePlaceSizingDrag()
 
 	if (_special_mouse_mode != WSM_SIZING) return true;
 
-	e.we.place.userdata = _thd.userdata;
+	e.we.place.select_method = _thd.select_method;
+	e.we.place.select_proc   = _thd.select_proc;
 
 	/* stop drag mode if the window has been closed */
 	w = FindWindowById(_thd.window_class, _thd.window_number);
@@ -2467,7 +2469,7 @@ bool VpHandlePlaceSizingDrag()
 	_special_mouse_mode = WSM_NONE;
 	if (_thd.next_drawstyle == HT_RECT) {
 		_thd.place_mode = VHM_RECT;
-	} else if ((e.we.place.userdata & 0xF) == VPM_SIGNALDIRS) { // some might call this a hack... -- Dominik
+	} else if (e.we.place.select_method == VPM_SIGNALDIRS) { // some might call this a hack... -- Dominik
 		_thd.place_mode = VHM_RECT;
 	} else if (_thd.next_drawstyle & HT_LINE) {
 		_thd.place_mode = VHM_RAIL;
diff --git a/src/viewport.h b/src/viewport.h
--- a/src/viewport.h
+++ b/src/viewport.h
@@ -62,7 +62,7 @@ void SetRedErrorSquare(TileIndex tile);
 void SetTileSelectSize(int w, int h);
 void SetTileSelectBigSize(int ox, int oy, int sx, int sy);
 
-void VpStartPlaceSizing(TileIndex tile, int user);
+void VpStartPlaceSizing(TileIndex tile, byte method, byte process);
 void VpSetPresizeRange(uint from, uint to);
 void VpSetPlaceSizingLimit(int limit);
 
@@ -137,7 +137,9 @@ struct TileHighlightData {
 	WindowClass window_class;
 	WindowNumber window_number;
 
-	int userdata;
+	byte select_method;
+	byte select_proc;
+
 	TileIndex redsq;
 };
 
diff --git a/src/window.h b/src/window.h
--- a/src/window.h
+++ b/src/window.h
@@ -135,7 +135,8 @@ struct WindowEvent {
 			Point pt;
 			TileIndex tile;
 			TileIndex starttile;
-			int userdata;
+			byte select_method;
+			byte select_proc;
 		} place;
 
 		struct {