diff --git a/src/widgets/dropdown.cpp b/src/widgets/dropdown.cpp
--- a/src/widgets/dropdown.cpp
+++ b/src/widgets/dropdown.cpp
@@ -22,7 +22,7 @@
 #include "../safeguards.h"
 
 
-void DropDownListItem::Draw(int left, int right, int top, int bottom, bool sel, int bg_colour) const
+void DropDownListItem::Draw(int left, int right, int top, int bottom, bool sel, Colours bg_colour) const
 {
 	int c1 = _colour_gradient[bg_colour][3];
 	int c2 = _colour_gradient[bg_colour][7];
@@ -39,7 +39,7 @@ uint DropDownListStringItem::Width() con
 	return GetStringBoundingBox(buffer).width;
 }
 
-void DropDownListStringItem::Draw(int left, int right, int top, int bottom, bool sel, int bg_colour) const
+void DropDownListStringItem::Draw(int left, int right, int top, int bottom, bool sel, Colours bg_colour) const
 {
 	DrawString(left + WD_FRAMERECT_LEFT, right - WD_FRAMERECT_RIGHT, top, this->String(), sel ? TC_WHITE : TC_BLACK);
 }