--- src/summaryview.c.orig	2005-10-12 07:27:20.000000000 +0300
+++ src/summaryview.c		2005-10-23 14:20:31.000000000 +0300
@@ -4392,7 +4392,7 @@
 
 	gtk_tree_view_enable_model_drag_source
 		(GTK_TREE_VIEW(treeview),
-		 0, summary_drag_types, N_DRAG_TYPES,
+		 GDK_BUTTON1_MASK, summary_drag_types, N_DRAG_TYPES,
 		 GDK_ACTION_MOVE | GDK_ACTION_COPY);
 
 	g_signal_connect_after(G_OBJECT(treeview), "drag-begin",