diff --git a/src/apps/activitymonitor/ActivityWindow.cpp b/src/apps/activitymonitor/ActivityWindow.cpp
index bf551d65e9..ed25bba1bc 100644
--- a/src/apps/activitymonitor/ActivityWindow.cpp
+++ b/src/apps/activitymonitor/ActivityWindow.cpp
@@ -44,7 +44,7 @@ ActivityWindow::ActivityWindow()
 	}
 
 #ifdef __HAIKU__
-	BGroupLayout* layout = new BGroupLayout(B_VERTICAL);
+	BGroupLayout* layout = new BGroupLayout(B_VERTICAL, 0);
 	SetLayout(layout);
 
 	// create GUI