diff --git a/src/command_type.h b/src/command_type.h
--- a/src/command_type.h
+++ b/src/command_type.h
@@ -186,6 +186,7 @@ enum Commands : uint16 {
 	CMD_REMOVE_SIGNALS,               ///< remove a signal
 	CMD_TERRAFORM_LAND,               ///< terraform a tile
 	CMD_BUILD_OBJECT,                 ///< build an object
+	CMD_BUILD_OBJECT_AREA,            ///< build an area of objects
 	CMD_BUILD_TUNNEL,                 ///< build a tunnel
 
 	CMD_REMOVE_FROM_RAIL_STATION,     ///< remove a (rectangle of) tiles from a rail station