diff --git a/src/newgrf_gui.cpp b/src/newgrf_gui.cpp
--- a/src/newgrf_gui.cpp
+++ b/src/newgrf_gui.cpp
@@ -578,7 +578,7 @@ public:
 		return true;
 	}
 
-	void Draw(int left, int right, int top, int bottom, bool sel, int bg_colour) const
+	void Draw(int left, int right, int top, int bottom, bool sel, Colours bg_colour) const
 	{
 		DrawString(left + 2, right + 2, top, _grf_preset_list[this->result], sel ? TC_WHITE : TC_BLACK);
 	}