diff --git a/headers/private/interface/BMCPrivate.h b/headers/private/interface/BMCPrivate.h
index 3843882dd0..c6f0bdead3 100644
--- a/headers/private/interface/BMCPrivate.h
+++ b/headers/private/interface/BMCPrivate.h
@@ -45,9 +45,11 @@ virtual	void		FrameResized(float width, float height);
 virtual	void		MessageReceived(BMessage* msg);
 virtual	void		MakeFocus(bool focused = true);
 
-	void		TogglePopUpMarker(bool show) { fShowPopUpMarker = show; }
-	bool		IsPopUpMarkerShown() const { return fShowPopUpMarker; }
-	
+		void		TogglePopUpMarker(bool show) { fShowPopUpMarker = show; }
+		bool		IsPopUpMarkerShown() const { return fShowPopUpMarker; }
+
+virtual	BSize		MaxSize();
+
 private:
 		_BMCMenuBar_&operator=(const _BMCMenuBar_ &);
 		
diff --git a/src/kits/interface/BMCPrivate.cpp b/src/kits/interface/BMCPrivate.cpp
index 82e02dcc4f..e817c93ca3 100644
--- a/src/kits/interface/BMCPrivate.cpp
+++ b/src/kits/interface/BMCPrivate.cpp
@@ -10,6 +10,7 @@
 #include <stdio.h>
 
 #include <BMCPrivate.h>
+#include <LayoutUtils.h>
 #include <MenuField.h>
 #include <MenuItem.h>
 #include <Message.h>
@@ -321,6 +322,17 @@ _BMCMenuBar_::MakeFocus(bool focused)
 }
 
 
+BSize
+_BMCMenuBar_::MaxSize()
+{
+	// The maximum width of a normal BMenuBar is unlimited, but we want it
+	// limited.
+	BSize size;
+	BMenuBar::GetPreferredSize(&size.width, &size.height);
+	return BLayoutUtils::ComposeSize(ExplicitMaxSize(), size);
+}
+
+
 _BMCMenuBar_ 
 &_BMCMenuBar_::operator=(const _BMCMenuBar_ &)
 {