(svn r2307) - Fix (regression): it was not possible to change the drive-side in the intro-game.

- CodeChange: remove unused "CANT_DO_THIS" double-string.

lang/english.txt

@@ -1595,7 +1595,6 @@ STR_2051_BUILD_A_STATUE_IN_HONOR                                :{WHITE}{STRING}
 STR_2052_FUND_THE_CONSTRUCTION_OF                               :{WHITE}{STRING}{}{YELLOW} Fund the construction of new commercial buildings in the town.{}  Cost: {CURRENCY}
 STR_2053_BUY_1_YEAR_S_EXCLUSIVE                                 :{WHITE}{STRING}{}{YELLOW} Buy 1 year's exclusive transport rights in town. Town authority will only allow passengers and cargo to use your company's stations.{} Cost: {CURRENCY}
 STR_TOWN_BRIBE_THE_LOCAL_AUTHORITY_DESC                         :{WHITE}{STRING}{}{YELLOW} Bribe the local authority to increase your rating, at the risk of a severe penalty if caught.{}  Cost: {CURRENCY}
-STR_2054_CAN_T_DO_THIS                                          :{WHITE}Can't do this...
 STR_2055_TRAFFIC_CHAOS_IN_ROAD_REBUILDING                       :{BIGFONT}{BLACK}Traffic chaos in {TOWN}!{}{}Road rebuilding programme funded by {STRING} brings 6 months of misery to motorists!
 STR_2056                                                        :{TINYFONT}{WHITE}{TOWN}
 STR_2057                                                        :{ORANGE}{TOWN}{BLACK} ({COMMA32})

settings_gui.c

@@ -70,7 +70,7 @@ static int GetCurRes(void)
 
 static inline bool RoadVehiclesAreBuilt(void)
 {
-	Vehicle *v;
+	const Vehicle *v;
 	FOR_ALL_VEHICLES(v) {
 		if (v->type == VEH_Road) return true;
 	}
@@ -171,7 +171,7 @@ static void GameOptionsWndProc(Window *w, WindowEvent *e)
 			break;
 		case 11: /* Road side */
 			if (_opt_ptr->road_side != e->dropdown.index) { // only change if setting changed
-				DoCommandP(0, e->dropdown.index, 0, NULL, CMD_SET_ROAD_DRIVE_SIDE | CMD_MSG(STR_EMPTY));
+				DoCommandP(0, e->dropdown.index, 0, NULL, CMD_SET_ROAD_DRIVE_SIDE | CMD_MSG(STR_00B4_CAN_T_DO_THIS));
 				MarkWholeScreenDirty();
 			}
 			break;
@@ -214,8 +214,9 @@ static void GameOptionsWndProc(Window *w, WindowEvent *e)
  */
 int32 CmdSetRoadDriveSide(int x, int y, uint32 flags, uint32 p1, uint32 p2)
 {
-	/* Check boundaries and you can only change this if NO vehicles have been built yet */
-	if (p1 > 1 || RoadVehiclesAreBuilt()) return CMD_ERROR;
+	/* Check boundaries and you can only change this if NO vehicles have been built yet,
+	 * except in the intro-menu where of course it's always possible to do so. */
+	if (p1 > 1 || (_game_mode != GM_MENU && RoadVehiclesAreBuilt())) return CMD_ERROR;
 
 	if (flags & DC_EXEC) {
 		_opt_ptr->road_side = p1;

town_gui.c

@@ -196,7 +196,7 @@ static void TownAuthorityWndProc(Window *w, WindowEvent *e)
 		}
 
 		case 6: { /* carry out the action */
-			DoCommandP(GetTown(w->window_number)->xy, w->window_number, WP(w,def_d).data_1, NULL, CMD_DO_TOWN_ACTION | CMD_MSG(STR_2054_CAN_T_DO_THIS));
+			DoCommandP(GetTown(w->window_number)->xy, w->window_number, WP(w,def_d).data_1, NULL, CMD_DO_TOWN_ACTION | CMD_MSG(STR_00B4_CAN_T_DO_THIS));
 			break;
 		}
 		}