diff --git a/projects/openttd.vcproj b/projects/openttd.vcproj
index 4ee36a3f5b..45042187fd 100644
--- a/projects/openttd.vcproj
+++ b/projects/openttd.vcproj
@@ -629,6 +629,9 @@
 			<File
 				RelativePath=".\..\src\train.h">
 			</File>
+			<File
+				RelativePath=".\..\src\transparency_gui.h">
+			</File>
 			<File
 				RelativePath=".\..\src\variables.h">
 			</File>
diff --git a/projects/openttd_vs80.vcproj b/projects/openttd_vs80.vcproj
index 4f15366379..57c9cfca4d 100644
--- a/projects/openttd_vs80.vcproj
+++ b/projects/openttd_vs80.vcproj
@@ -1067,6 +1067,10 @@
 				RelativePath=".\..\src\train.h"
 				>
 			</File>
+			<File
+				RelativePath=".\..\src\transparency_gui.h"
+				>
+			</File>
 			<File
 				RelativePath=".\..\src\variables.h"
 				>
diff --git a/source.list b/source.list
index b8fb9a0fe9..a172190b91 100644
--- a/source.list
+++ b/source.list
@@ -177,6 +177,7 @@ thread.h
 tile.h
 town.h
 train.h
+transparency_gui.h
 variables.h
 vehicle.h
 vehicle_gui.h
diff --git a/src/transparency_gui.h b/src/transparency_gui.h
new file mode 100644
index 0000000000..8ecb03a73e
--- /dev/null
+++ b/src/transparency_gui.h
@@ -0,0 +1,8 @@
+/* $Id$ */
+
+#ifndef TRANSPARENCY_GUI_H
+#define TRANSPARENCY_GUI_H
+
+void ShowTransparencyToolbar();
+
+#endif /* TRANSPARENCY_GUI_H */