(svn r21716) -Add: Tooltip for the industry legend at the smallmap.

src/lang/english.txt

@@ -664,6 +664,7 @@ STR_SMALLMAP_TOOLTIP_SHOW_INDUSTRIES_ON_MAP                     :{BLACK}Show ind
 STR_SMALLMAP_TOOLTIP_SHOW_TRANSPORT_ROUTES_ON                   :{BLACK}Show transport routes on map
 STR_SMALLMAP_TOOLTIP_SHOW_VEGETATION_ON_MAP                     :{BLACK}Show vegetation on map
 STR_SMALLMAP_TOOLTIP_SHOW_LAND_OWNERS_ON_MAP                    :{BLACK}Show land owners on map
+STR_SMALLMAP_TOOLTIP_INDUSTRY_SELECTION                         :{BLACK}Click on an industry type to toggle displaying it. Ctrl+Click disables all types except the selected one. Ctrl+Click on it again to enable all industry types
 
 STR_SMALLMAP_LEGENDA_ROADS                                      :{TINYFONT}{BLACK}Roads
 STR_SMALLMAP_LEGENDA_RAILROADS                                  :{TINYFONT}{BLACK}Railways

src/smallmap_gui.cpp

@@ -992,6 +992,8 @@ public:
 
 		this->SetWidgetLoweredState(SM_WIDGET_TOGGLETOWNNAME, this->show_towns);
 		this->GetWidget<NWidgetStacked>(SM_WIDGET_SELECTINDUSTRIES)->SetDisplayedPlane(this->map_type != SMT_INDUSTRY);
+		this->GetWidget<NWidgetCore>(SM_WIDGET_LEGEND)->SetDataTip(STR_NULL,
+				(this->map_type == SMT_INDUSTRY) ? STR_SMALLMAP_TOOLTIP_INDUSTRY_SELECTION : STR_NULL);
 
 		this->SetZoomLevel(ZLC_INITIALIZE, NULL);
 		this->SmallMapCenterOnCurrentPos();
@@ -1153,6 +1155,9 @@ public:
 		/* Hide Enable all/Disable all buttons if is not industry type small map */
 		this->GetWidget<NWidgetStacked>(SM_WIDGET_SELECTINDUSTRIES)->SetDisplayedPlane(this->map_type != SMT_INDUSTRY);
 
+		this->GetWidget<NWidgetCore>(SM_WIDGET_LEGEND)->SetDataTip(STR_NULL,
+				(this->map_type == SMT_INDUSTRY) ? STR_SMALLMAP_TOOLTIP_INDUSTRY_SELECTION : STR_NULL);
+
 		this->SetDirty();
 	}