diff --git a/include/Desktop/accel.h b/include/Desktop/accel.h
index aa7ee57..fa59bf5 100644
--- a/include/Desktop/accel.h
+++ b/include/Desktop/accel.h
@@ -30,7 +30,7 @@ typedef struct _DesktopAccel
 
 
 /* functions */
-void desktop_accel_create(DesktopAccel * accel, gpointer data,
+void desktop_accel_create(DesktopAccel const * accel, gpointer data,
 		GtkAccelGroup * group);
 
 #endif /* !LIBDESKTOP_ACCEL_H */
diff --git a/include/Desktop/menubar.h b/include/Desktop/menubar.h
index a7180c4..901db23 100644
--- a/include/Desktop/menubar.h
+++ b/include/Desktop/menubar.h
@@ -33,12 +33,12 @@ typedef struct _DesktopMenu
 typedef struct _DesktopMenubar
 {
 	const char * name;
-	DesktopMenu * menu;
+	const DesktopMenu * menu;
 } DesktopMenubar;
 
 
 /* functions */
-GtkWidget * desktop_menubar_create(DesktopMenubar * menubar, gpointer data,
-		GtkAccelGroup * accel);
+GtkWidget * desktop_menubar_create(DesktopMenubar const * menubar,
+		gpointer data, GtkAccelGroup * accel);
 
 #endif /* !LIBDESKTOP_MENUBAR_H */
diff --git a/include/Desktop/toolbar.h b/include/Desktop/toolbar.h
index 4130425..22cfca4 100644
--- a/include/Desktop/toolbar.h
+++ b/include/Desktop/toolbar.h
@@ -33,7 +33,7 @@ typedef struct _DesktopToolbar
 
 
 /* functions */
-GtkWidget * desktop_toolbar_create(DesktopToolbar * toolbar, gpointer data,
-		GtkAccelGroup * accel);
+GtkWidget * desktop_toolbar_create(DesktopToolbar const * toolbar,
+		gpointer data, GtkAccelGroup * accel);
 
 #endif /* !LIBDESKTOP_TOOLBAR_H */
diff --git a/src/accel.c b/src/accel.c
index bb13d2e..6ec34ec 100644
--- a/src/accel.c
+++ b/src/accel.c
@@ -20,7 +20,7 @@
 
 /* Accel */
 /* desktop_accel_create */
-void desktop_accel_create(DesktopAccel * accel, gpointer data,
+void desktop_accel_create(DesktopAccel const * accel, gpointer data,
 		GtkAccelGroup * group)
 {
 	size_t i;
diff --git a/src/menubar.c b/src/menubar.c
index 982f04d..aad85de 100644
--- a/src/menubar.c
+++ b/src/menubar.c
@@ -27,8 +27,8 @@ static GtkWidget * _menubar_create_menu(DesktopMenu * menu, gpointer data,
 		GtkAccelGroup * accel);
 static GtkWidget * _menubar_create_menu_from_image(DesktopMenu * menu);
 
-GtkWidget * desktop_menubar_create(DesktopMenubar * menubar, gpointer data,
-		GtkAccelGroup * accel)
+GtkWidget * desktop_menubar_create(DesktopMenubar const * menubar,
+		gpointer data, GtkAccelGroup * accel)
 {
 	GtkWidget * ret;
 	GtkWidget * menuitem;
diff --git a/src/toolbar.c b/src/toolbar.c
index 83dea3e..26426a8 100644
--- a/src/toolbar.c
+++ b/src/toolbar.c
@@ -23,8 +23,8 @@
 
 /* Toolbar */
 /* desktop_toolbar_create */
-GtkWidget * desktop_toolbar_create(DesktopToolbar * toolbar, gpointer data,
-		GtkAccelGroup * accel)
+GtkWidget * desktop_toolbar_create(DesktopToolbar const * toolbar,
+		gpointer data, GtkAccelGroup * accel)
 {
 	GtkWidget * ret;
 	size_t i;