Feature: Show the number of industries already built in the Fund New Industry window.

src/industry_cmd.cpp

@@ -207,6 +207,7 @@ Industry::~Industry()
 void Industry::PostDestructor(size_t index)
 {
 	InvalidateWindowData(WC_INDUSTRY_DIRECTORY, 0, IDIWD_FORCE_REBUILD);
+	SetWindowDirty(WC_BUILD_INDUSTRY, 0);
 }
 
 
@@ -1942,6 +1943,7 @@ static void DoCreateNewIndustry(Industry *i, TileIndex tile, IndustryType type,
 		for (uint j = 0; j != 50; j++) PlantRandomFarmField(i);
 	}
 	InvalidateWindowData(WC_INDUSTRY_DIRECTORY, 0, IDIWD_FORCE_REBUILD);
+	SetWindowDirty(WC_BUILD_INDUSTRY, 0);
 
 	if (!_generating_world) PopulateStationsNearby(i);
 }

src/industry_gui.cpp

@@ -517,14 +517,16 @@ public:
 				icon.bottom = icon.top + this->legend.height - 1;
 
 				for (uint16 i = this->vscroll->GetPosition(); this->vscroll->IsVisible(i) && i < this->vscroll->GetCount(); i++) {
-					bool selected = this->selected_type == this->list[i];
-
-					const IndustrySpec *indsp = GetIndustrySpec(this->list[i]);
+					IndustryType type = this->list[i];
+					bool selected = this->selected_type == type;
+					const IndustrySpec *indsp = GetIndustrySpec(type);
 
 					/* Draw the name of the industry in white is selected, otherwise, in orange */
 					DrawString(text, indsp->name, selected ? TC_WHITE : TC_ORANGE);
 					GfxFillRect(icon, selected ? PC_WHITE : PC_BLACK);
 					GfxFillRect(icon.Shrink(WidgetDimensions::scaled.bevel), indsp->map_colour);
+					SetDParam(0, Industry::GetIndustryTypeCount(type));
+					DrawString(text, STR_JUST_COMMA, TC_BLACK, SA_RIGHT, false, FS_SMALL);
 
 					text = text.Translate(0, this->resize.step_height);
 					icon = icon.Translate(0, this->resize.step_height);