diff --git a/src/openrct2-ui/windows/TopToolbar.cpp b/src/openrct2-ui/windows/TopToolbar.cpp
index 591768ec1e..7a07e0099d 100644
--- a/src/openrct2-ui/windows/TopToolbar.cpp
+++ b/src/openrct2-ui/windows/TopToolbar.cpp
@@ -291,7 +291,10 @@ static money32 selection_raise_land(uint8 flags);
 static bool     _menuDropdownIncludesTwitch;
 static uint8    _unkF64F0E;
 static sint16   _unkF64F0A;
-static uint16   _unkF64F15;
+// rct2: 0x00F64F15
+static colour_t _secondaryColour;
+// rct2: 0x00F64F16
+static colour_t _tertiaryColour;
 
 /**
  * Creates the main game top toolbar window.
@@ -1440,7 +1443,8 @@ static void sub_6E1F34(sint16 x, sint16 y, uint16 selected_scenery, sint16* grid
         if (*grid_x == LOCATION_NULL)
             return;
 
-        _unkF64F15 = gWindowScenerySecondaryColour | (gWindowSceneryTertiaryColour << 8);
+        _secondaryColour = gWindowScenerySecondaryColour;
+        _tertiaryColour = gWindowSceneryTertiaryColour;
         // Also places it in lower but think thats for clobbering
         *parameter_1 = (selected_scenery & 0xFF) << 8;
         *parameter_2 = cl | (gWindowSceneryPrimaryColour << 8);
@@ -1694,7 +1698,7 @@ static void window_top_toolbar_scenery_tool_down(sint16 x, sint16 y, rct_window
 
             gDisableErrorWindowSound = true;
             gGameCommandErrorTitle = STR_CANT_BUILD_PARK_ENTRANCE_HERE;
-            sint32 cost = game_do_command(gridX, flags, gridY, parameter_2, GAME_COMMAND_PLACE_WALL, gSceneryPlaceZ, _unkF64F15);
+            sint32 cost = game_do_command(gridX, flags, gridY, parameter_2, GAME_COMMAND_PLACE_WALL, gSceneryPlaceZ, _secondaryColour | (_tertiaryColour << 8));
             gDisableErrorWindowSound = false;
 
             if (cost != MONEY32_UNDEFINED){
@@ -2296,7 +2300,7 @@ static money32 try_place_ghost_scenery(LocationXY16 map_tile, uint32 parameter_1
             parameter_2,
             GAME_COMMAND_PLACE_WALL,
             gSceneryPlaceZ,
-            _unkF64F15);
+            _secondaryColour | (_tertiaryColour << 8));
 
         if (cost == MONEY32_UNDEFINED)
             return cost;