(svn r26450) -Feature: Hierarchical vehicle subgroups.

11 files changed, 218 insertions, 51 deletions

diff --git a/src/autoreplace.cpp b/src/autoreplace.cpp
index 0cb8d997f..0788fccb3 100644
--- a/src/autoreplace.cpp
+++ b/src/autoreplace.cpp
@@ -28,7 +28,7 @@ static EngineRenew *GetEngineReplacement(EngineRenewList erl, EngineID engine, G
 	EngineRenew *er = (EngineRenew *)erl;
 
 	while (er != NULL) {
-		if (er->from == engine && er->group_id == group) return er;
+		if (er->from == engine && GroupIsInGroup(group, er->group_id)) return er;
 		er = er->next;
 	}
 	return NULL;
diff --git a/src/command.cpp b/src/command.cpp
index 2891a06af..34d5ab61e 100644
--- a/src/command.cpp
+++ b/src/command.cpp
@@ -180,7 +180,7 @@ CommandProc CmdDepotSellAllVehicles;
 CommandProc CmdDepotMassAutoReplace;
 
 CommandProc CmdCreateGroup;
-CommandProc CmdRenameGroup;
+CommandProc CmdAlterGroup;
 CommandProc CmdDeleteGroup;
 CommandProc CmdAddVehicleGroup;
 CommandProc CmdAddSharedVehicleGroup;
@@ -338,7 +338,7 @@ static const Command _command_proc_table[] = {
 	DEF_CMD(CmdDepotMassAutoReplace,                           0, CMDT_VEHICLE_CONSTRUCTION  ), // CMD_DEPOT_MASS_AUTOREPLACE
 	DEF_CMD(CmdCreateGroup,                                    0, CMDT_ROUTE_MANAGEMENT      ), // CMD_CREATE_GROUP
 	DEF_CMD(CmdDeleteGroup,                                    0, CMDT_ROUTE_MANAGEMENT      ), // CMD_DELETE_GROUP
-	DEF_CMD(CmdRenameGroup,                                    0, CMDT_OTHER_MANAGEMENT      ), // CMD_RENAME_GROUP
+	DEF_CMD(CmdAlterGroup,                                     0, CMDT_OTHER_MANAGEMENT      ), // CMD_ALTER_GROUP
 	DEF_CMD(CmdAddVehicleGroup,                                0, CMDT_ROUTE_MANAGEMENT      ), // CMD_ADD_VEHICLE_GROUP
 	DEF_CMD(CmdAddSharedVehicleGroup,                          0, CMDT_ROUTE_MANAGEMENT      ), // CMD_ADD_SHARE_VEHICLE_GROUP
 	DEF_CMD(CmdRemoveAllVehiclesGroup,                         0, CMDT_ROUTE_MANAGEMENT      ), // CMD_REMOVE_ALL_VEHICLES_GROUP
diff --git a/src/command_type.h b/src/command_type.h
index b4a49bd9f..a369be665 100644
--- a/src/command_type.h
+++ b/src/command_type.h
@@ -314,7 +314,7 @@ enum Commands {
 
 	CMD_CREATE_GROUP,                 ///< create a new group
 	CMD_DELETE_GROUP,                 ///< delete a group
-	CMD_RENAME_GROUP,                 ///< rename a group
+	CMD_ALTER_GROUP,                  ///< alter a group
 	CMD_ADD_VEHICLE_GROUP,            ///< add a vehicle to a group
 	CMD_ADD_SHARED_VEHICLE_GROUP,     ///< add all other shared vehicles to a group which are missing
 	CMD_REMOVE_ALL_VEHICLES_GROUP,    ///< remove all vehicles from a group
diff --git a/src/group.h b/src/group.h
index d8680c294..91ee77e60 100644
--- a/src/group.h
+++ b/src/group.h
@@ -71,6 +71,8 @@ struct Group : GroupPool::PoolItem<&_group_pool> {
 	bool replace_protection;                ///< If set to true, the global autoreplace have no effect on the group
 	GroupStatistics statistics;             ///< NOSAVE: Statistics and caches on the vehicles in the group.
 
+	GroupID parent;                         ///< Parent group
+
 	Group(CompanyID owner = INVALID_COMPANY);
 	~Group();
 };
@@ -101,6 +103,7 @@ void SetTrainGroupID(Train *v, GroupID grp);
 void UpdateTrainGroupID(Train *v);
 void RemoveVehicleFromGroup(const Vehicle *v);
 void RemoveAllGroupsForCompany(const CompanyID company);
+bool GroupIsInGroup(GroupID search, GroupID group);
 
 extern GroupID _new_group_id;
 
diff --git a/src/group_cmd.cpp b/src/group_cmd.cpp
index e86b9de28..77e0b0d38 100644
--- a/src/group_cmd.cpp
+++ b/src/group_cmd.cpp
@@ -285,6 +285,7 @@ CommandCost CmdCreateGroup(TileIndex tile, DoCommandFlag flags, uint32 p1, uint3
 		Group *g = new Group(_current_company);
 		g->replace_protection = false;
 		g->vehicle_type = vt;
+		g->parent = INVALID_GROUP;
 
 		_new_group_id = g->index;
 
@@ -313,6 +314,14 @@ CommandCost CmdDeleteGroup(TileIndex tile, DoCommandFlag flags, uint32 p1, uint3
 	/* Remove all vehicles from the group */
 	DoCommand(0, p1, 0, flags, CMD_REMOVE_ALL_VEHICLES_GROUP);
 
+	/* Delete sub-groups */
+	Group *gp;
+	FOR_ALL_GROUPS(gp) {
+		if (gp->parent == g->index) {
+			DoCommand(0, gp->index, 0, flags, CMD_DELETE_GROUP);
+		}
+	}
+
 	if (flags & DC_EXEC) {
 		/* Update backupped orders if needed */
 		OrderBackup::ClearGroup(g->index);
@@ -352,33 +361,60 @@ static bool IsUniqueGroupNameForVehicleType(const char *name, VehicleType type)
 }
 
 /**
- * Rename a group
+ * Alter a group
  * @param tile unused
  * @param flags type of operation
  * @param p1   index of array group
  *   - p1 bit 0-15 : GroupID
- * @param p2   unused
+ *   - p1 bit 16: 0 - Rename grouop
+ *                1 - Set group parent
+ * @param p2   parent group index
  * @param text the new name or an empty string when resetting to the default
  * @return the cost of this operation or an error
  */
-CommandCost CmdRenameGroup(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32 p2, const char *text)
+CommandCost CmdAlterGroup(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32 p2, const char *text)
 {
-	Group *g = Group::GetIfValid(p1);
+	Group *g = Group::GetIfValid(GB(p1, 0, 16));
 	if (g == NULL || g->owner != _current_company) return CMD_ERROR;
 
-	bool reset = StrEmpty(text);
+	if (!HasBit(p1, 16)) {
+		/* Rename group */
+		bool reset = StrEmpty(text);
+
+		if (!reset) {
+			if (Utf8StringLength(text) >= MAX_LENGTH_GROUP_NAME_CHARS) return CMD_ERROR;
+			if (!IsUniqueGroupNameForVehicleType(text, g->vehicle_type)) return_cmd_error(STR_ERROR_NAME_MUST_BE_UNIQUE);
+		}
 
-	if (!reset) {
-		if (Utf8StringLength(text) >= MAX_LENGTH_GROUP_NAME_CHARS) return CMD_ERROR;
-		if (!IsUniqueGroupNameForVehicleType(text, g->vehicle_type)) return_cmd_error(STR_ERROR_NAME_MUST_BE_UNIQUE);
+		if (flags & DC_EXEC) {
+			/* Delete the old name */
+			free(g->name);
+			/* Assign the new one */
+			g->name = reset ? NULL : strdup(text);
+		}
+	} else {
+		/* Set group parent */
+		const Group *pg = Group::GetIfValid(GB(p2, 0, 16));
+
+		if (pg != NULL) {
+			if (pg->owner != _current_company) return CMD_ERROR;
+			if (pg->vehicle_type != g->vehicle_type) return CMD_ERROR;
+
+			/* Ensure request parent isn't child of group.
+			 * This is the only place that infinite loops are prevented. */
+			const Group *looptest = pg;
+			while (looptest->parent != INVALID_GROUP) {
+				if (looptest->parent == g->index) return CMD_ERROR;
+				looptest = Group::Get(looptest->parent);
+			}
+		}
+
+		if (flags & DC_EXEC) {
+			g->parent = (pg == NULL) ? INVALID_GROUP : pg->index;
+		}
 	}
 
 	if (flags & DC_EXEC) {
-		/* Delete the old name */
-		free(g->name);
-		/* Assign the new one */
-		g->name = reset ? NULL : strdup(text);
-
 		SetWindowDirty(WC_REPLACE_VEHICLE, g->vehicle_type);
 		InvalidateWindowData(GetWindowClassForVehicleType(g->vehicle_type), VehicleListIdentifier(VL_GROUP_LIST, g->vehicle_type, _current_company).Pack());
 	}
@@ -542,6 +578,20 @@ CommandCost CmdRemoveAllVehiclesGroup(TileIndex tile, DoCommandFlag flags, uint3
 	return CommandCost();
 }
 
+/**
+ * Set replace protection for a group and its sub-groups.
+ * @param g initial group.
+ * @param protect 1 to set or 0 to clear protection.
+ */
+static void SetGroupReplaceProtection(Group *g, bool protect)
+{
+	g->replace_protection = protect;
+
+	Group *pg;
+	FOR_ALL_GROUPS(pg) {
+		if (pg->parent == g->index) SetGroupReplaceProtection(pg, protect);
+	}
+}
 
 /**
  * (Un)set global replace protection from a group
@@ -551,6 +601,7 @@ CommandCost CmdRemoveAllVehiclesGroup(TileIndex tile, DoCommandFlag flags, uint3
  * - p1 bit 0-15 : GroupID
  * @param p2
  * - p2 bit 0    : 1 to set or 0 to clear protection.
+ * - p2 bit 1    : 1 to apply to sub-groups.
  * @param text unused
  * @return the cost of this operation or an error
  */
@@ -560,7 +611,11 @@ CommandCost CmdSetGroupReplaceProtection(TileIndex tile, DoCommandFlag flags, ui
 	if (g == NULL || g->owner != _current_company) return CMD_ERROR;
 
 	if (flags & DC_EXEC) {
-		g->replace_protection = HasBit(p2, 0);
+		if (HasBit(p2, 1)) {
+			SetGroupReplaceProtection(g, HasBit(p2, 0));
+		} else {
+			g->replace_protection = HasBit(p2, 0);
+		}
 
 		SetWindowDirty(GetWindowClassForVehicleType(g->vehicle_type), VehicleListIdentifier(VL_GROUP_LIST, g->vehicle_type, _current_company).Pack());
 		InvalidateWindowData(WC_REPLACE_VEHICLE, g->vehicle_type);
@@ -639,8 +694,13 @@ void UpdateTrainGroupID(Train *v)
  */
 uint GetGroupNumEngines(CompanyID company, GroupID id_g, EngineID id_e)
 {
+	uint count = 0;
 	const Engine *e = Engine::Get(id_e);
-	return GroupStatistics::Get(company, id_g, e->type).num_engines[id_e];
+	const Group *g;
+	FOR_ALL_GROUPS(g) {
+		if (g->parent == id_g) count += GetGroupNumEngines(company, g->index, id_e);
+	}
+	return count + GroupStatistics::Get(company, id_g, e->type).num_engines[id_e];
 }
 
 void RemoveAllGroupsForCompany(const CompanyID company)
@@ -651,3 +711,19 @@ void RemoveAllGroupsForCompany(const CompanyID company)
 		if (company == g->owner) delete g;
 	}
 }
+
+
+bool GroupIsInGroup(GroupID search, GroupID group)
+{
+	if (search == NEW_GROUP ||
+	    search == ALL_GROUP ||
+	    search == DEFAULT_GROUP ||
+	    search == INVALID_GROUP) return search == group;
+
+	do {
+		if (search == group) return true;
+		search = Group::Get(search)->parent;
+	} while (search != INVALID_GROUP);
+
+	return false;
+}
diff --git a/src/group_gui.cpp b/src/group_gui.cpp
index ed3176e27..698f9a71f 100644
--- a/src/group_gui.cpp
+++ b/src/group_gui.cpp
@@ -30,6 +30,8 @@
 
 #include "table/sprites.h"
 
+static const int LEVEL_WIDTH = 10; ///< Indenting width of a sub-group in pixels
+
 typedef GUIList<const Group*> GUIGroupList;
 
 static const NWidgetPart _nested_group_widgets[] = {
@@ -105,34 +107,26 @@ private:
 	};
 
 	VehicleID vehicle_sel; ///< Selected vehicle
+	GroupID group_sel;     ///< Selected group (for drag/drop)
 	GroupID group_rename;  ///< Group being renamed, INVALID_GROUP if none
 	GroupID group_over;    ///< Group over which a vehicle is dragged, INVALID_GROUP if none
 	GUIGroupList groups;   ///< List of groups
 	uint tiny_step_height; ///< Step height for the group list
 	Scrollbar *group_sb;
 
+	SmallVector<int, 16> indents; ///< Indentation levels
+
 	Dimension column_size[VGC_END]; ///< Size of the columns in the group list.
 
-	/**
-	 * (Re)Build the group list.
-	 *
-	 * @param owner The owner of the window
-	 */
-	void BuildGroupList(Owner owner)
+	void AddParents(GUIGroupList *source, GroupID parent, int indent)
 	{
-		if (!this->groups.NeedRebuild()) return;
-
-		this->groups.Clear();
-
-		const Group *g;
-		FOR_ALL_GROUPS(g) {
-			if (g->owner == owner && g->vehicle_type == this->vli.vtype) {
-				*this->groups.Append() = g;
+		for (const Group **g = source->Begin(); g != source->End(); g++) {
+			if ((*g)->parent == parent) {
+				*this->groups.Append() = *g;
+				*this->indents.Append() = indent;
+				AddParents(source, (*g)->index, indent + 1);
 			}
 		}
-
-		this->groups.Compact();
-		this->groups.RebuildDone();
 	}
 
 	/** Sort the groups by their name */
@@ -159,6 +153,36 @@ private:
 	}
 
 	/**
+	 * (Re)Build the group list.
+	 *
+	 * @param owner The owner of the window
+	 */
+	void BuildGroupList(Owner owner)
+	{
+		if (!this->groups.NeedRebuild()) return;
+
+		this->groups.Clear();
+		this->indents.Clear();
+
+		GUIGroupList list;
+
+		const Group *g;
+		FOR_ALL_GROUPS(g) {
+			if (g->owner == owner && g->vehicle_type == this->vli.vtype) {
+				*list.Append() = g;
+			}
+		}
+
+		list.ForceResort();
+		list.Sort(&GroupNameSorter);
+
+		AddParents(&list, INVALID_GROUP, 0);
+
+		this->groups.Compact();
+		this->groups.RebuildDone();
+	}
+
+	/**
 	 * Compute tiny_step_height and column_size
 	 * @return Total width required for the group list.
 	 */
@@ -204,9 +228,10 @@ private:
 	 * @param left Left of the row.
 	 * @param right Right of the row.
 	 * @param g_id Group to list.
+	 * @param indent Indentation level.
 	 * @param protection Whether autoreplace protection is set.
 	 */
-	void DrawGroupInfo(int y, int left, int right, GroupID g_id, bool protection = false) const
+	void DrawGroupInfo(int y, int left, int right, GroupID g_id, int indent = 0, bool protection = false) const
 	{
 		/* Highlight the group if a vehicle is dragged over it */
 		if (g_id == this->group_over) {
@@ -231,7 +256,7 @@ private:
 			str = STR_GROUP_NAME;
 		}
 		int x = rtl ? right - WD_FRAMERECT_RIGHT - 8 - this->column_size[VGC_NAME].width + 1 : left + WD_FRAMERECT_LEFT + 8;
-		DrawString(x, x + this->column_size[VGC_NAME].width - 1, y + (this->tiny_step_height - this->column_size[VGC_NAME].height) / 2, str, colour);
+		DrawString(x + indent * LEVEL_WIDTH, x + this->column_size[VGC_NAME].width - 1, y + (this->tiny_step_height - this->column_size[VGC_NAME].height) / 2, str, colour);
 
 		/* draw autoreplace protection */
 		x = rtl ? x - 8 - this->column_size[VGC_PROTECT].width : x + 8 + this->column_size[VGC_NAME].width;
@@ -295,6 +320,7 @@ public:
 
 		this->vli.index = ALL_GROUP;
 		this->vehicle_sel = INVALID_VEHICLE;
+		this->group_sel = INVALID_GROUP;
 		this->group_rename = INVALID_GROUP;
 		this->group_over = INVALID_GROUP;
 
@@ -308,7 +334,6 @@ public:
 		this->groups.ForceRebuild();
 		this->groups.NeedResort();
 		this->BuildGroupList(vli.company);
-		this->groups.Sort(&GroupNameSorter);
 
 		this->GetWidget<NWidgetCore>(WID_GL_CAPTION)->widget_data = STR_VEHICLE_LIST_TRAIN_CAPTION + this->vli.vtype;
 		this->GetWidget<NWidgetCore>(WID_GL_LIST_VEHICLE)->tool_tip = STR_VEHICLE_LIST_TRAIN_LIST_TOOLTIP + this->vli.vtype;
@@ -442,7 +467,6 @@ public:
 		this->SortVehicleList();
 
 		this->BuildGroupList(this->owner);
-		this->groups.Sort(&GroupNameSorter);
 
 		this->group_sb->SetCount(this->groups.Length());
 		this->vscroll->SetCount(this->vehicles.Length());
@@ -508,7 +532,7 @@ public:
 
 					assert(g->owner == this->owner);
 
-					DrawGroupInfo(y1, r.left, r.right, g->index, g->replace_protection);
+					DrawGroupInfo(y1, r.left, r.right, g->index, this->indents[i], g->replace_protection);
 
 					y1 += this->tiny_step_height;
 				}
@@ -523,6 +547,19 @@ public:
 				break;
 
 			case WID_GL_LIST_VEHICLE:
+				if (this->vli.index != ALL_GROUP) {
+					/* Mark vehicles which are in sub-groups */
+					int y = r.top;
+					uint max = min(this->vscroll->GetPosition() + this->vscroll->GetCapacity(), this->vehicles.Length());
+					for (uint i = this->vscroll->GetPosition(); i < max; ++i) {
+						const Vehicle *v = this->vehicles[i];
+						if (v->group_id != this->vli.index) {
+							GfxFillRect(r.left + 1, y + 1, r.right - 1, y + this->resize.step_height - 2, _colour_gradient[COLOUR_GREY][3], FILLRECT_CHECKER);
+						}
+						y += this->resize.step_height;
+					}
+				}
+
 				this->DrawVehicleListItems(this->vehicle_sel, this->resize.step_height, r);
 				break;
 		}
@@ -560,7 +597,9 @@ public:
 				uint id_g = this->group_sb->GetScrolledRowFromWidget(pt.y, this, WID_GL_LIST_GROUP, 0, this->tiny_step_height);
 				if (id_g >= this->groups.Length()) return;
 
-				this->vli.index = this->groups[id_g]->index;
+				this->group_sel = this->vli.index = this->groups[id_g]->index;
+
+				SetObjectToPlaceWnd(SPR_CURSOR_MOUSE, PAL_NONE, HT_DRAG, this);
 
 				this->vehicles.ForceRebuild();
 				this->SetDirty();
@@ -620,14 +659,46 @@ public:
 			case WID_GL_REPLACE_PROTECTION: {
 				const Group *g = Group::GetIfValid(this->vli.index);
 				if (g != NULL) {
-					DoCommandP(0, this->vli.index, !g->replace_protection, CMD_SET_GROUP_REPLACE_PROTECTION);
+					DoCommandP(0, this->vli.index, !g->replace_protection | (_ctrl_pressed << 1), CMD_SET_GROUP_REPLACE_PROTECTION);
 				}
 				break;
 			}
 		}
 	}
 
-	virtual void OnDragDrop(Point pt, int widget)
+	void OnDragDrop_Group(Point pt, int widget)
+	{
+		const Group *g = Group::Get(this->group_sel);
+
+		switch (widget) {
+			case WID_GL_ALL_VEHICLES: // All vehicles
+			case WID_GL_DEFAULT_VEHICLES: // Ungroupd vehicles
+				if (g->parent != INVALID_GROUP) {
+					DoCommandP(0, this->group_sel | (1 << 16), INVALID_GROUP, CMD_ALTER_GROUP | CMD_MSG(STR_ERROR_GROUP_CAN_T_SET_PARENT));
+				}
+
+				this->group_sel = INVALID_GROUP;
+				this->group_over = INVALID_GROUP;
+				this->SetDirty();
+				break;
+
+			case WID_GL_LIST_GROUP: { // Matrix group
+				uint id_g = this->group_sb->GetScrolledRowFromWidget(pt.y, this, WID_GL_LIST_GROUP, 0, this->tiny_step_height);
+				GroupID new_g = id_g >= this->groups.Length() ? INVALID_GROUP : this->groups[id_g]->index;
+
+				if (this->group_sel != new_g && g->parent != new_g) {
+					DoCommandP(0, this->group_sel | (1 << 16), new_g, CMD_ALTER_GROUP | CMD_MSG(STR_ERROR_GROUP_CAN_T_SET_PARENT));
+				}
+
+				this->group_sel = INVALID_GROUP;
+				this->group_over = INVALID_GROUP;
+				this->SetDirty();
+				break;
+			}
+		}
+	}
+
+	void OnDragDrop_Vehicle(Point pt, int widget)
 	{
 		switch (widget) {
 			case WID_GL_DEFAULT_VEHICLES: // Ungrouped vehicles
@@ -668,12 +739,19 @@ public:
 				break;
 			}
 		}
+	}
+
+	virtual void OnDragDrop(Point pt, int widget)
+	{
+		if (this->vehicle_sel != INVALID_VEHICLE) OnDragDrop_Vehicle(pt, widget);
+		if (this->group_sel != INVALID_GROUP) OnDragDrop_Group(pt, widget);
+
 		_cursor.vehchain = false;
 	}
 
 	virtual void OnQueryTextFinished(char *str)
 	{
-		if (str != NULL) DoCommandP(0, this->group_rename, 0, CMD_RENAME_GROUP | CMD_MSG(STR_ERROR_GROUP_CAN_T_RENAME), NULL, str);
+		if (str != NULL) DoCommandP(0, this->group_rename, 0, CMD_ALTER_GROUP | CMD_MSG(STR_ERROR_GROUP_CAN_T_RENAME), NULL, str);
 		this->group_rename = INVALID_GROUP;
 	}
 
@@ -742,7 +820,7 @@ public:
 
 	virtual void OnMouseDrag(Point pt, int widget)
 	{
-		if (this->vehicle_sel == INVALID_VEHICLE) return;
+		if (this->vehicle_sel == INVALID_VEHICLE && this->group_sel == INVALID_GROUP) return;
 
 		/* A vehicle is dragged over... */
 		GroupID new_group_over = INVALID_GROUP;
@@ -759,7 +837,11 @@ public:
 		}
 
 		/* Do not highlight when dragging over the current group */
-		if (Vehicle::Get(vehicle_sel)->group_id == new_group_over) new_group_over = INVALID_GROUP;
+		if (this->vehicle_sel != INVALID_VEHICLE) {
+			if (Vehicle::Get(vehicle_sel)->group_id == new_group_over) new_group_over = INVALID_GROUP;
+		} else if (this->group_sel != INVALID_GROUP) {
+			if (this->group_sel == new_group_over || Group::Get(this->group_sel)->parent == new_group_over) new_group_over = INVALID_GROUP;
+		}
 
 		/* Mark widgets as dirty if the group changed. */
 		if (new_group_over != this->group_over) {
diff --git a/src/lang/english.txt b/src/lang/english.txt
index 198515a34..7bf97aaa3 100644
--- a/src/lang/english.txt
+++ b/src/lang/english.txt
@@ -3297,7 +3297,7 @@ STR_GROUP_DEFAULT_ROAD_VEHICLES                                 :Ungrouped road
 STR_GROUP_DEFAULT_SHIPS                                         :Ungrouped ships
 STR_GROUP_DEFAULT_AIRCRAFTS                                     :Ungrouped aircraft
 
-STR_GROUPS_CLICK_ON_GROUP_FOR_TOOLTIP                           :{BLACK}Groups - click on a group to list all vehicles of this group
+STR_GROUPS_CLICK_ON_GROUP_FOR_TOOLTIP                           :{BLACK}Groups - click on a group to list all vehicles of this group. Drag and drop groups to arrange hierarchy.
 STR_GROUP_CREATE_TOOLTIP                                        :{BLACK}Click to create a group
 STR_GROUP_DELETE_TOOLTIP                                        :{BLACK}Delete the selected group
 STR_GROUP_RENAME_TOOLTIP                                        :{BLACK}Rename the selected group
@@ -4276,6 +4276,7 @@ STR_ERROR_YOU_ALREADY_OWN_IT                                    :{WHITE}... you
 STR_ERROR_GROUP_CAN_T_CREATE                                    :{WHITE}Can't create group...
 STR_ERROR_GROUP_CAN_T_DELETE                                    :{WHITE}Can't delete this group...
 STR_ERROR_GROUP_CAN_T_RENAME                                    :{WHITE}Can't rename group...
+STR_ERROR_GROUP_CAN_T_SET_PARENT                                :{WHITE}Can't set parent group...
 STR_ERROR_GROUP_CAN_T_REMOVE_ALL_VEHICLES                       :{WHITE}Can't remove all vehicles from this group...
 STR_ERROR_GROUP_CAN_T_ADD_VEHICLE                               :{WHITE}Can't add the vehicle to this group...
 STR_ERROR_GROUP_CAN_T_ADD_SHARED_VEHICLE                        :{WHITE}Can't add shared vehicles to group...
diff --git a/src/saveload/group_sl.cpp b/src/saveload/group_sl.cpp
index 1e006a218..891d6ea6f 100644
--- a/src/saveload/group_sl.cpp
+++ b/src/saveload/group_sl.cpp
@@ -21,6 +21,7 @@ static const SaveLoad _group_desc[] = {
 	     SLE_VAR(Group, owner,              SLE_UINT8),
 	     SLE_VAR(Group, vehicle_type,       SLE_UINT8),
 	     SLE_VAR(Group, replace_protection, SLE_BOOL),
+	 SLE_CONDVAR(Group, parent,             SLE_UINT16,                    189, SL_MAX_VERSION),
 	     SLE_END()
 };
 
@@ -42,6 +43,8 @@ static void Load_GRPS()
 	while ((index = SlIterateArray()) != -1) {
 		Group *g = new (index) Group();
 		SlObject(g, _group_desc);
+
+		if (IsSavegameVersionBefore(189)) g->parent = INVALID_GROUP;
 	}
 }
 
diff --git a/src/saveload/saveload.cpp b/src/saveload/saveload.cpp
index e1daaf405..ab3e4a290 100644
--- a/src/saveload/saveload.cpp
+++ b/src/saveload/saveload.cpp
@@ -254,8 +254,9 @@
  *  186   25833
  *  187   25899
  *  188   26169   1.4.x
+ *  189   26450
  */
-extern const uint16 SAVEGAME_VERSION = 188; ///< Current savegame version of OpenTTD.
+extern const uint16 SAVEGAME_VERSION = 189; ///< Current savegame version of OpenTTD.
 
 SavegameType _savegame_type; ///< type of savegame we are loading
 
diff --git a/src/script/api/script_group.cpp b/src/script/api/script_group.cpp
index 01569d824..89cbf2c71 100644
--- a/src/script/api/script_group.cpp
+++ b/src/script/api/script_group.cpp
@@ -57,7 +57,7 @@
 	EnforcePreconditionEncodedText(false, text);
 	EnforcePreconditionCustomError(false, ::Utf8StringLength(text) < MAX_LENGTH_GROUP_NAME_CHARS, ScriptError::ERR_PRECONDITION_STRING_TOO_LONG);
 
-	return ScriptObject::DoCommand(0, group_id, 0, CMD_RENAME_GROUP, text);
+	return ScriptObject::DoCommand(0, group_id, 0, CMD_ALTER_GROUP, text);
 }
 
 /* static */ char *ScriptGroup::GetName(GroupID group_id)
diff --git a/src/vehiclelist.cpp b/src/vehiclelist.cpp
index e74f28f0f..fca9c5e46 100644
--- a/src/vehiclelist.cpp
+++ b/src/vehiclelist.cpp
@@ -12,6 +12,7 @@
 #include "stdafx.h"
 #include "train.h"
 #include "vehiclelist.h"
+#include "group.h"
 
 /**
  * Pack a VehicleListIdentifier in a single uint32.
@@ -145,7 +146,7 @@ bool GenerateVehicleSortList(VehicleList *list, const VehicleListIdentifier &vli
 			if (vli.index != ALL_GROUP) {
 				FOR_ALL_VEHICLES(v) {
 					if (v->type == vli.vtype && v->IsPrimaryVehicle() &&
-							v->owner == vli.company && v->group_id == vli.index) {
+							v->owner == vli.company && GroupIsInGroup(v->group_id, vli.index)) {
 						*list->Append() = v;
 					}
 				}