Feature: Option to group vehicle lists by shared orders

This applies to all kinds of vehicle lists, as well as the "vehicle groups" window.

6 files changed, 296 insertions, 54 deletions

diff --git a/src/group_gui.cpp b/src/group_gui.cpp
index 5323b65f2..c5d9ac599 100644
--- a/src/group_gui.cpp
+++ b/src/group_gui.cpp
@@ -72,6 +72,11 @@ static const NWidgetPart _nested_group_widgets[] = {
 		/* right part */
 		NWidget(NWID_VERTICAL),
 			NWidget(NWID_HORIZONTAL),
+				NWidget(WWT_TEXTBTN, COLOUR_GREY, WID_GL_GROUP_BY_ORDER), SetMinimalSize(81, 12), SetDataTip(STR_STATION_VIEW_GROUP, STR_TOOLTIP_GROUP_ORDER),
+				NWidget(WWT_DROPDOWN, COLOUR_GREY, WID_GL_GROUP_BY_DROPDOWN), SetMinimalSize(167, 12), SetDataTip(0x0, STR_TOOLTIP_GROUP_ORDER),
+				NWidget(WWT_PANEL, COLOUR_GREY), SetMinimalSize(12, 12), SetResize(1, 0), EndContainer(),
+			EndContainer(),
+			NWidget(NWID_HORIZONTAL),
 				NWidget(WWT_PUSHTXTBTN, COLOUR_GREY, WID_GL_SORT_BY_ORDER), SetMinimalSize(81, 12), SetDataTip(STR_BUTTON_SORT_BY, STR_TOOLTIP_SORT_ORDER),
 				NWidget(WWT_DROPDOWN, COLOUR_GREY, WID_GL_SORT_BY_DROPDOWN), SetMinimalSize(167, 12), SetDataTip(0x0, STR_TOOLTIP_SORT_CRITERIA),
 				NWidget(WWT_PANEL, COLOUR_GREY), SetMinimalSize(12, 12), SetResize(1, 0), EndContainer(),
@@ -537,8 +542,11 @@ public:
 		if (!IsDefaultGroupID(this->vli.index) && !IsAllGroupID(this->vli.index) && Group::Get(this->vli.index)->replace_protection) protect_sprite = SPR_GROUP_REPLACE_ON_TRAIN;
 		this->GetWidget<NWidgetCore>(WID_GL_REPLACE_PROTECTION)->widget_data = protect_sprite + this->vli.vtype;
 
-		/* Set text of sort by dropdown */
-		this->GetWidget<NWidgetCore>(WID_GL_SORT_BY_DROPDOWN)->widget_data = this->vehicle_group_none_sorter_names[this->vehgroups.SortType()];
+		/* Set text of "group by" dropdown widget. */
+		this->GetWidget<NWidgetCore>(WID_GL_GROUP_BY_DROPDOWN)->widget_data = this->vehicle_group_by_names[this->grouping];
+
+		/* Set text of "sort by" dropdown widget. */
+		this->GetWidget<NWidgetCore>(WID_GL_SORT_BY_DROPDOWN)->widget_data = this->GetVehicleSorterNames()[this->vehgroups.SortType()];
 
 		this->DrawWidgets();
 	}
@@ -650,6 +658,10 @@ public:
 				this->SetDirty();
 				break;
 
+			case WID_GL_GROUP_BY_DROPDOWN: // Select grouping option dropdown menu
+				ShowDropDownMenu(this, this->vehicle_group_by_names, this->grouping, WID_GL_GROUP_BY_DROPDOWN, 0, 0);
+				return;
+
 			case WID_GL_SORT_BY_DROPDOWN: // Select sorting criteria dropdown menu
 				ShowDropDownMenu(this, this->GetVehicleSorterNames(), this->vehgroups.SortType(),  WID_GL_SORT_BY_DROPDOWN, 0, (this->vli.vtype == VEH_TRAIN || this->vli.vtype == VEH_ROAD) ? 0 : (1 << 10));
 				return;
@@ -715,19 +727,35 @@ public:
 				if (id_v >= this->vehgroups.size()) return; // click out of list bound
 
 				const GUIVehicleGroup &vehgroup = this->vehgroups[id_v];
-				const Vehicle * const v = vehgroup.GetSingleVehicle();
+				switch (this->grouping) {
+					case GB_NONE: {
+						const Vehicle *v = vehgroup.GetSingleVehicle();
+						if (VehicleClicked(v)) break;
 
-				this->vehicle_sel = v->index;
+						this->vehicle_sel = v->index;
 
-				if (_ctrl_pressed) {
-					this->SelectGroup(v->group_id);
-				}
+						if (_ctrl_pressed) {
+							this->SelectGroup(v->group_id);
+						}
 
-				SetObjectToPlaceWnd(SPR_CURSOR_MOUSE, PAL_NONE, HT_DRAG, this);
-				SetMouseCursorVehicle(v, EIT_IN_LIST);
-				_cursor.vehchain = true;
+						SetObjectToPlaceWnd(SPR_CURSOR_MOUSE, PAL_NONE, HT_DRAG, this);
+						SetMouseCursorVehicle(v, EIT_IN_LIST);
+						_cursor.vehchain = true;
+
+						this->SetDirty();
+						break;
+					}
+
+					case GB_SHARED_ORDERS:
+						assert(vehgroup.NumVehicles() > 0);
+						/* No drag-and-drop support for shared order grouping; we immediately open the shared orders window */
+						ShowVehicleListWindow(vehgroup.vehicles_begin[0]);
+						break;
+
+					default:
+						NOT_REACHED();
+				}
 
-				this->SetDirty();
 				break;
 			}
 
@@ -842,10 +870,21 @@ public:
 				if (id_v >= this->vehgroups.size()) return; // click out of list bound
 
 				const GUIVehicleGroup &vehgroup = this->vehgroups[id_v];
-				const Vehicle *v = vehgroup.GetSingleVehicle();
-				if (!VehicleClicked(v) && vindex == v->index) {
-					ShowVehicleViewWindow(v);
+				switch (this->grouping) {
+					case GB_NONE: {
+						const Vehicle *v = vehgroup.GetSingleVehicle();
+						if (!VehicleClicked(v) && vindex == v->index) {
+							ShowVehicleViewWindow(v);
+						}
+						break;
+					}
+					case GB_SHARED_ORDERS:
+						/* Currently no drag-and-drop support when grouped by shared orders.  Modify this if we want to support some drag-drop behaviour for shared order list items. */
+						NOT_REACHED();
+					default:
+						NOT_REACHED();
 				}
+				break;
 			}
 		}
 	}
@@ -873,6 +912,10 @@ public:
 	void OnDropdownSelect(int widget, int index) override
 	{
 		switch (widget) {
+			case WID_GL_GROUP_BY_DROPDOWN:
+				this->UpdateVehicleGroupBy(static_cast<GroupBy>(index));
+				break;
+
 			case WID_GL_SORT_BY_DROPDOWN:
 				this->vehgroups.SetSortType(index);
 				break;
diff --git a/src/lang/english.txt b/src/lang/english.txt
index 6d11d2d76..2b96f1931 100644
--- a/src/lang/english.txt
+++ b/src/lang/english.txt
@@ -315,6 +315,15 @@ STR_SORT_BY_CARGO_CAPACITY                                      :Cargo capacity
 STR_SORT_BY_RANGE                                               :Range
 STR_SORT_BY_POPULATION                                          :Population
 STR_SORT_BY_RATING                                              :Rating
+STR_SORT_BY_NUM_VEHICLES                                        :Number of vehicles
+STR_SORT_BY_TOTAL_PROFIT_LAST_YEAR                              :Total profit last year
+STR_SORT_BY_TOTAL_PROFIT_THIS_YEAR                              :Total profit this year
+STR_SORT_BY_AVERAGE_PROFIT_LAST_YEAR                            :Average profit last year
+STR_SORT_BY_AVERAGE_PROFIT_THIS_YEAR                            :Average profit this year
+
+# Group by options for vehicle list
+STR_GROUP_BY_NONE                                               :None
+STR_GROUP_BY_SHARED_ORDERS                                      :Shared orders
 
 # Tooltips for the main toolbar
 STR_TOOLBAR_TOOLTIP_PAUSE_GAME                                  :{BLACK}Pause game
diff --git a/src/vehicle_gui.cpp b/src/vehicle_gui.cpp
index 135da393a..a1b40ba92 100644
--- a/src/vehicle_gui.cpp
+++ b/src/vehicle_gui.cpp
@@ -58,6 +58,11 @@ static BaseVehicleListWindow::VehicleIndividualSortFunction VehicleValueSorter;
 static BaseVehicleListWindow::VehicleIndividualSortFunction VehicleLengthSorter;
 static BaseVehicleListWindow::VehicleIndividualSortFunction VehicleTimeToLiveSorter;
 static BaseVehicleListWindow::VehicleIndividualSortFunction VehicleTimetableDelaySorter;
+static BaseVehicleListWindow::VehicleGroupSortFunction VehicleGroupLengthSorter;
+static BaseVehicleListWindow::VehicleGroupSortFunction VehicleGroupTotalProfitThisYearSorter;
+static BaseVehicleListWindow::VehicleGroupSortFunction VehicleGroupTotalProfitLastYearSorter;
+static BaseVehicleListWindow::VehicleGroupSortFunction VehicleGroupAverageProfitThisYearSorter;
+static BaseVehicleListWindow::VehicleGroupSortFunction VehicleGroupAverageProfitLastYearSorter;
 
 /** Wrapper to convert a VehicleIndividualSortFunction to a VehicleGroupSortFunction */
 template <BaseVehicleListWindow::VehicleIndividualSortFunction func>
@@ -99,6 +104,29 @@ const StringID BaseVehicleListWindow::vehicle_group_none_sorter_names[] = {
 	INVALID_STRING_ID
 };
 
+BaseVehicleListWindow::VehicleGroupSortFunction * const BaseVehicleListWindow::vehicle_group_shared_orders_sorter_funcs[] = {
+	&VehicleGroupLengthSorter,
+	&VehicleGroupTotalProfitThisYearSorter,
+	&VehicleGroupTotalProfitLastYearSorter,
+	&VehicleGroupAverageProfitThisYearSorter,
+	&VehicleGroupAverageProfitLastYearSorter,
+};
+
+const StringID BaseVehicleListWindow::vehicle_group_shared_orders_sorter_names[] = {
+	STR_SORT_BY_NUM_VEHICLES,
+	STR_SORT_BY_TOTAL_PROFIT_THIS_YEAR,
+	STR_SORT_BY_TOTAL_PROFIT_LAST_YEAR,
+	STR_SORT_BY_AVERAGE_PROFIT_THIS_YEAR,
+	STR_SORT_BY_AVERAGE_PROFIT_LAST_YEAR,
+	INVALID_STRING_ID
+};
+
+const StringID BaseVehicleListWindow::vehicle_group_by_names[] = {
+	STR_GROUP_BY_NONE,
+	STR_GROUP_BY_SHARED_ORDERS,
+	INVALID_STRING_ID
+};
+
 const StringID BaseVehicleListWindow::vehicle_depot_name[] = {
 	STR_VEHICLE_LIST_SEND_TRAIN_TO_DEPOT,
 	STR_VEHICLE_LIST_SEND_ROAD_VEHICLE_TO_DEPOT,
@@ -156,16 +184,50 @@ void BaseVehicleListWindow::BuildVehicleList()
 
 	GenerateVehicleSortList(&this->vehicles, this->vli);
 
-	uint max_unitnumber = 0;
-	for (auto it = this->vehicles.begin(); it != this->vehicles.end(); ++it) {
-		this->vehgroups.emplace_back(it, it + 1, (*it)->GetDisplayProfitThisYear(), (*it)->GetDisplayProfitLastYear(), (*it)->age);
+	if (this->grouping == GB_NONE) {
+		uint max_unitnumber = 0;
+		for (auto it = this->vehicles.begin(); it != this->vehicles.end(); ++it) {
+			this->vehgroups.emplace_back(it, it + 1, (*it)->GetDisplayProfitThisYear(), (*it)->GetDisplayProfitLastYear(), (*it)->age);
+
+			max_unitnumber = max<uint>(max_unitnumber, (*it)->unitnumber);
+		}
+		this->unitnumber_digits = CountDigitsForAllocatingSpace(max_unitnumber);
+	} else {
+		/* Sort by the primary vehicle; we just want all vehicles that share the same orders to form a contiguous range. */
+		std::stable_sort(this->vehicles.begin(), this->vehicles.end(), [](const Vehicle * const &u, const Vehicle * const &v) {
+			return u->FirstShared() < v->FirstShared();
+		});
+
+		uint max_num_vehicles = 0;
+
+		VehicleList::const_iterator begin = this->vehicles.begin();
+		while (begin != this->vehicles.end()) {
+			VehicleList::const_iterator end = std::find_if_not(begin, this->vehicles.cend(), [first_shared = (*begin)->FirstShared()](const Vehicle * const &v) {
+				return v->FirstShared() == first_shared;
+			});
+
+			Money display_profit_this_year = 0;
+			Money display_profit_last_year = 0;
+			Date age = 0;
+			for (auto it = begin; it != end; ++it) {
+				const Vehicle * const v = (*it);
+				display_profit_this_year += v->GetDisplayProfitThisYear();
+				display_profit_last_year += v->GetDisplayProfitLastYear();
+				age = max<Date>(age, v->age);
+			}
 
-		max_unitnumber = max<uint>(max_unitnumber, (*it)->unitnumber);
+			this->vehgroups.emplace_back(begin, end, display_profit_this_year, display_profit_last_year, age);
+
+			max_num_vehicles = max<uint>(max_num_vehicles, static_cast<uint>(end - begin));
+
+			begin = end;
+		}
+
+		this->unitnumber_digits = CountDigitsForAllocatingSpace(max_num_vehicles);
 	}
-	this->unitnumber_digits = CountDigitsForAllocatingSpace(max_unitnumber);
 
 	this->vehgroups.RebuildDone();
-	this->vscroll->SetCount(this->vehgroups.size());
+	this->vscroll->SetCount(static_cast<int>(this->vehgroups.size()));
 }
 
 /**
@@ -1114,6 +1176,36 @@ StringID GetCargoSubtypeText(const Vehicle *v)
 	return STR_EMPTY;
 }
 
+/** Sort vehicle groups by the number of vehicles in the group */
+static bool VehicleGroupLengthSorter(const GUIVehicleGroup &a, const GUIVehicleGroup &b)
+{
+	return a.NumVehicles() < b.NumVehicles();
+}
+
+/** Sort vehicle groups by the total profit this year */
+static bool VehicleGroupTotalProfitThisYearSorter(const GUIVehicleGroup &a, const GUIVehicleGroup &b)
+{
+	return a.display_profit_this_year < b.display_profit_this_year;
+}
+
+/** Sort vehicle groups by the total profit last year */
+static bool VehicleGroupTotalProfitLastYearSorter(const GUIVehicleGroup &a, const GUIVehicleGroup &b)
+{
+	return a.display_profit_last_year < b.display_profit_last_year;
+}
+
+/** Sort vehicle groups by the average profit this year */
+static bool VehicleGroupAverageProfitThisYearSorter(const GUIVehicleGroup &a, const GUIVehicleGroup &b)
+{
+	return a.display_profit_this_year * static_cast<uint>(b.NumVehicles()) < b.display_profit_this_year * static_cast<uint>(a.NumVehicles());
+}
+
+/** Sort vehicle groups by the average profit last year */
+static bool VehicleGroupAverageProfitLastYearSorter(const GUIVehicleGroup &a, const GUIVehicleGroup &b)
+{
+	return a.display_profit_last_year * static_cast<uint>(b.NumVehicles()) < b.display_profit_last_year * static_cast<uint>(a.NumVehicles());
+}
+
 /** Sort vehicles by their number */
 static bool VehicleNumberSorter(const Vehicle * const &a, const Vehicle * const &b)
 {
@@ -1290,6 +1382,12 @@ static const NWidgetPart _nested_vehicle_list[] = {
 	EndContainer(),
 
 	NWidget(NWID_HORIZONTAL),
+		NWidget(WWT_TEXTBTN, COLOUR_GREY, WID_VL_GROUP_ORDER), SetMinimalSize(81, 12), SetFill(0, 1), SetDataTip(STR_STATION_VIEW_GROUP, STR_TOOLTIP_GROUP_ORDER),
+		NWidget(WWT_DROPDOWN, COLOUR_GREY, WID_VL_GROUP_BY_PULLDOWN), SetMinimalSize(167, 12), SetFill(0, 1), SetDataTip(0x0, STR_TOOLTIP_GROUP_ORDER),
+		NWidget(WWT_PANEL, COLOUR_GREY), SetMinimalSize(12, 12), SetFill(1, 1), SetResize(1, 0), EndContainer(),
+	EndContainer(),
+
+	NWidget(NWID_HORIZONTAL),
 		NWidget(WWT_PUSHTXTBTN, COLOUR_GREY, WID_VL_SORT_ORDER), SetMinimalSize(81, 12), SetFill(0, 1), SetDataTip(STR_BUTTON_SORT_BY, STR_TOOLTIP_SORT_ORDER),
 		NWidget(WWT_DROPDOWN, COLOUR_GREY, WID_VL_SORT_BY_PULLDOWN), SetMinimalSize(167, 12), SetFill(0, 1), SetDataTip(0x0, STR_TOOLTIP_SORT_CRITERIA),
 		NWidget(WWT_PANEL, COLOUR_GREY), SetMinimalSize(12, 12), SetFill(1, 1), SetResize(1, 0),
@@ -1352,6 +1450,25 @@ static void DrawSmallOrderList(const Vehicle *v, int left, int right, int y, Veh
 	} while (oid != start);
 }
 
+/** Draw small order list in the vehicle GUI, but without the little black arrow.  This is used for shared order groups. */
+static void DrawSmallOrderList(const Order *order, int left, int right, int y)
+{
+	bool rtl = _current_text_dir == TD_RTL;
+	int l_offset = rtl ? 0 : ScaleGUITrad(6);
+	int r_offset = rtl ? ScaleGUITrad(6) : 0;
+	int i = 0;
+	while (order != nullptr) {
+		if (order->IsType(OT_GOTO_STATION)) {
+			SetDParam(0, order->GetDestination());
+			DrawString(left + l_offset, right - r_offset, y, STR_TINY_BLACK_STATION);
+
+			y += FONT_HEIGHT_SMALL;
+			if (++i == 4) break;
+		}
+		order = order->next;
+	}
+}
+
 /**
  * Draws an image of a vehicle chain
  * @param v         Front vehicle
@@ -1419,7 +1536,7 @@ void BaseVehicleListWindow::DrawVehicleListItems(VehicleID selected_vehicle, int
 	int vehicle_button_x = rtl ? right - GetSpriteSize(SPR_PROFIT_LOT).width : left;
 
 	int y = r.top;
-	uint max = min(this->vscroll->GetPosition() + this->vscroll->GetCapacity(), this->vehgroups.size());
+	uint max = min(this->vscroll->GetPosition() + this->vscroll->GetCapacity(), static_cast<uint>(this->vehgroups.size()));
 	for (uint i = this->vscroll->GetPosition(); i < max; ++i) {
 
 		const GUIVehicleGroup &vehgroup = this->vehgroups[i];
@@ -1430,31 +1547,54 @@ void BaseVehicleListWindow::DrawVehicleListItems(VehicleID selected_vehicle, int
 
 		DrawVehicleProfitButton(vehgroup.age, vehgroup.display_profit_last_year, vehgroup.NumVehicles(), vehicle_button_x, y + FONT_HEIGHT_NORMAL + 3);
 
-		const Vehicle *v = vehgroup.GetSingleVehicle();
+		switch (this->grouping) {
+			case GB_NONE: {
+				const Vehicle *v = vehgroup.GetSingleVehicle();
 
-		DrawVehicleImage(v, image_left, image_right, y + FONT_HEIGHT_SMALL - 1, selected_vehicle, EIT_IN_LIST, 0);
+				DrawVehicleImage(v, image_left, image_right, y + FONT_HEIGHT_SMALL - 1, selected_vehicle, EIT_IN_LIST, 0);
 
-		if (!v->name.empty()) {
-			/* The vehicle got a name so we will print it */
-			SetDParam(0, v->index);
-			DrawString(text_left, text_right, y, STR_TINY_BLACK_VEHICLE);
-		} else if (v->group_id != DEFAULT_GROUP) {
-			/* The vehicle has no name, but is member of a group, so print group name */
-			SetDParam(0, v->group_id);
-			DrawString(text_left, text_right, y, STR_TINY_GROUP, TC_BLACK);
-		}
+				if (!v->name.empty()) {
+					/* The vehicle got a name so we will print it */
+					SetDParam(0, v->index);
+					DrawString(text_left, text_right, y, STR_TINY_BLACK_VEHICLE);
+				} else if (v->group_id != DEFAULT_GROUP) {
+					/* The vehicle has no name, but is member of a group, so print group name */
+					SetDParam(0, v->group_id);
+					DrawString(text_left, text_right, y, STR_TINY_GROUP, TC_BLACK);
+				}
 
-		if (show_orderlist) DrawSmallOrderList(v, orderlist_left, orderlist_right, y, v->cur_real_order_index);
+				if (show_orderlist) DrawSmallOrderList(v, orderlist_left, orderlist_right, y, v->cur_real_order_index);
 
-		StringID str;
-		if (v->IsChainInDepot()) {
-			str = STR_BLUE_COMMA;
-		} else {
-			str = (v->age > v->max_age - DAYS_IN_LEAP_YEAR) ? STR_RED_COMMA : STR_BLACK_COMMA;
-		}
+				StringID str;
+				if (v->IsChainInDepot()) {
+					str = STR_BLUE_COMMA;
+				} else {
+					str = (v->age > v->max_age - DAYS_IN_LEAP_YEAR) ? STR_RED_COMMA : STR_BLACK_COMMA;
+				}
 
-		SetDParam(0, v->unitnumber);
-		DrawString(left, right, y + 2, str);
+				SetDParam(0, v->unitnumber);
+				DrawString(left, right, y + 2, str);
+				break;
+			}
+
+			case GB_SHARED_ORDERS:
+
+				assert(vehgroup.NumVehicles() > 0);
+
+				for (int i = 0; i < static_cast<int>(vehgroup.NumVehicles()); ++i) {
+					if (image_left + 8 * i >= image_right) break; // Break if there is no more space to draw any more vehicles anyway.
+					DrawVehicleImage(vehgroup.vehicles_begin[i], image_left + 8 * i, image_right, y + FONT_HEIGHT_SMALL - 1, selected_vehicle, EIT_IN_LIST, 0);
+				}
+
+				if (show_orderlist) DrawSmallOrderList((vehgroup.vehicles_begin[0])->GetFirstOrder(), orderlist_left, orderlist_right, y);
+
+				SetDParam(0, vehgroup.NumVehicles());
+				DrawString(left, right, y + 2, STR_BLACK_COMMA);
+				break;
+
+			default:
+				NOT_REACHED();
+		}
 
 		y += line_height;
 	}
@@ -1472,7 +1612,7 @@ void BaseVehicleListWindow::UpdateSortingFromGrouping()
 		case VEH_AIRCRAFT: this->sorting = &_sorting[this->grouping].aircraft; break;
 		default: NOT_REACHED();
 	}
-	this->vehgroups.SetSortFuncs(this->vehicle_group_none_sorter_funcs);
+	this->vehgroups.SetSortFuncs(this->GetVehicleSorterFuncs());
 	this->vehgroups.SetListing(*this->sorting);
 	this->vehgroups.ForceRebuild();
 	this->vehgroups.NeedResort();
@@ -1523,6 +1663,10 @@ public:
 
 		if (this->vli.type == VL_SHARED_ORDERS) {
 			this->GetWidget<NWidgetCore>(WID_VL_CAPTION)->widget_data = STR_VEHICLE_LIST_SHARED_ORDERS_LIST_CAPTION;
+			/* If we are in the shared orders window, then disable the group-by dropdown menu.
+			 * Remove this when the group-by dropdown menu has another option apart from grouping by shared orders. */
+			this->SetWidgetDisabledState(WID_VL_GROUP_ORDER, true);
+			this->SetWidgetDisabledState(WID_VL_GROUP_BY_PULLDOWN, true);
 		} else {
 			this->GetWidget<NWidgetCore>(WID_VL_CAPTION)->widget_data = STR_VEHICLE_LIST_TRAIN_CAPTION + this->vli.vtype;
 		}
@@ -1656,8 +1800,11 @@ public:
 				WIDGET_LIST_END);
 		}
 
+		/* Set text of group by dropdown widget. */
+		this->GetWidget<NWidgetCore>(WID_VL_GROUP_BY_PULLDOWN)->widget_data = this->vehicle_group_by_names[this->grouping];
+
 		/* Set text of sort by dropdown widget. */
-		this->GetWidget<NWidgetCore>(WID_VL_SORT_BY_PULLDOWN)->widget_data = this->vehicle_group_none_sorter_names[this->vehgroups.SortType()];
+		this->GetWidget<NWidgetCore>(WID_VL_SORT_BY_PULLDOWN)->widget_data = this->GetVehicleSorterNames()[this->vehgroups.SortType()];
 
 		this->DrawWidgets();
 	}
@@ -1670,8 +1817,12 @@ public:
 				this->SetDirty();
 				break;
 
-			case WID_VL_SORT_BY_PULLDOWN:// Select sorting criteria dropdown menu
-				ShowDropDownMenu(this, this->vehicle_group_none_sorter_names, this->vehgroups.SortType(), WID_VL_SORT_BY_PULLDOWN, 0,
+			case WID_VL_GROUP_BY_PULLDOWN: // Select sorting criteria dropdown menu
+				ShowDropDownMenu(this, this->vehicle_group_by_names, this->grouping, WID_VL_GROUP_BY_PULLDOWN, 0, 0);
+				return;
+
+			case WID_VL_SORT_BY_PULLDOWN: // Select sorting criteria dropdown menu
+				ShowDropDownMenu(this, this->GetVehicleSorterNames(), this->vehgroups.SortType(), WID_VL_SORT_BY_PULLDOWN, 0,
 						(this->vli.vtype == VEH_TRAIN || this->vli.vtype == VEH_ROAD) ? 0 : (1 << 10));
 				return;
 
@@ -1680,15 +1831,29 @@ public:
 				if (id_v >= this->vehgroups.size()) return; // click out of list bound
 
 				const GUIVehicleGroup &vehgroup = this->vehgroups[id_v];
-				const Vehicle *v = vehgroup.GetSingleVehicle();
-
-				if (!VehicleClicked(v)) {
-					if (_ctrl_pressed) {
-						ShowCompanyGroupForVehicle(v);
-					} else {
-						ShowVehicleViewWindow(v);
+				switch (this->grouping) {
+					case GB_NONE: {
+						const Vehicle *v = vehgroup.GetSingleVehicle();
+						if (!VehicleClicked(v)) {
+							if (_ctrl_pressed) {
+								ShowCompanyGroupForVehicle(v);
+							} else {
+								ShowVehicleViewWindow(v);
+							}
+						}
+						break;
 					}
+
+					case GB_SHARED_ORDERS:
+						assert(vehgroup.NumVehicles() > 0);
+						/* We do not support VehicleClicked() here since the contextual action may only make sense for individual vehicles */
+
+						ShowVehicleListWindow(vehgroup.vehicles_begin[0]);
+						break;
+
+					default: NOT_REACHED();
 				}
+
 				break;
 			}
 
@@ -1711,9 +1876,14 @@ public:
 	void OnDropdownSelect(int widget, int index) override
 	{
 		switch (widget) {
+			case WID_VL_GROUP_BY_PULLDOWN:
+				this->UpdateVehicleGroupBy(static_cast<GroupBy>(index));
+				break;
+
 			case WID_VL_SORT_BY_PULLDOWN:
 				this->vehgroups.SetSortType(index);
 				break;
+
 			case WID_VL_MANAGE_VEHICLES_DROPDOWN:
 				assert(this->vehicles.size() != 0);
 
@@ -1729,6 +1899,7 @@ public:
 					default: NOT_REACHED();
 				}
 				break;
+
 			default: NOT_REACHED();
 		}
 		this->SetDirty();
diff --git a/src/vehicle_gui_base.h b/src/vehicle_gui_base.h
index c63d5ec18..f89b81ffb 100644
--- a/src/vehicle_gui_base.h
+++ b/src/vehicle_gui_base.h
@@ -49,6 +49,7 @@ struct BaseVehicleListWindow : public Window {
 
 	enum GroupBy : byte {
 		GB_NONE,
+		GB_SHARED_ORDERS,
 
 		GB_END,
 	};
@@ -92,12 +93,26 @@ struct BaseVehicleListWindow : public Window {
 
 	const StringID *GetVehicleSorterNames()
 	{
-		return vehicle_group_none_sorter_names;
+		switch (this->grouping) {
+			case GB_NONE:
+				return vehicle_group_none_sorter_names;
+			case GB_SHARED_ORDERS:
+				return vehicle_group_shared_orders_sorter_names;
+			default:
+				NOT_REACHED();
+		}
 	}
 
 	VehicleGroupSortFunction * const *GetVehicleSorterFuncs()
 	{
-		return vehicle_group_none_sorter_funcs;
+		switch (this->grouping) {
+			case GB_NONE:
+				return vehicle_group_none_sorter_funcs;
+			case GB_SHARED_ORDERS:
+				return vehicle_group_shared_orders_sorter_funcs;
+			default:
+				NOT_REACHED();
+		}
 	}
 };
 
diff --git a/src/widgets/group_widget.h b/src/widgets/group_widget.h
index beca5a3a6..03ac61a48 100644
--- a/src/widgets/group_widget.h
+++ b/src/widgets/group_widget.h
@@ -13,6 +13,8 @@
 /** Widgets of the #VehicleGroupWindow class. */
 enum GroupListWidgets {
 	WID_GL_CAPTION,                  ///< Caption of the window.
+	WID_GL_GROUP_BY_ORDER,           ///< Group order.
+	WID_GL_GROUP_BY_DROPDOWN,        ///< Group by dropdown list.
 	WID_GL_SORT_BY_ORDER,            ///< Sort order.
 	WID_GL_SORT_BY_DROPDOWN,         ///< Sort by dropdown list.
 	WID_GL_LIST_VEHICLE,             ///< List of the vehicles.
diff --git a/src/widgets/vehicle_widget.h b/src/widgets/vehicle_widget.h
index 5ecb8dffe..0ee1b2624 100644
--- a/src/widgets/vehicle_widget.h
+++ b/src/widgets/vehicle_widget.h
@@ -61,6 +61,8 @@ enum VehicleDetailsWidgets {
 /** Widgets of the #VehicleListWindow class. */
 enum VehicleListWidgets {
 	WID_VL_CAPTION,                  ///< Caption of window.
+	WID_VL_GROUP_ORDER,              ///< Group order.
+	WID_VL_GROUP_BY_PULLDOWN,        ///< Group by dropdown list.
 	WID_VL_SORT_ORDER,               ///< Sort order.
 	WID_VL_SORT_BY_PULLDOWN,         ///< Sort by dropdown list.
 	WID_VL_LIST,                     ///< List of the vehicles.