Index: plugins/vcdiff.c
===================================================================
--- plugins/vcdiff.c	(revision 2048)
+++ plugins/vcdiff.c	(working copy)
@@ -458,17 +458,21 @@
 {
 	document	*doc;
 	gboolean	have_file;
-	gboolean    have_vc = FALSE;
+	gboolean	have_vc = FALSE;
+	gboolean	project_have_vc = FALSE;
 
 	doc = documents->get_current();
 	have_file = doc && doc->file_name && g_path_is_absolute(doc->file_name);
-	if (find_cmd_env(VC_COMMAND_DIFF_FILE, TRUE, doc->file_name))
+	if (have_file && find_cmd_env(VC_COMMAND_DIFF_FILE, TRUE, doc->file_name))
 		have_vc = TRUE;
+	
+	if (project != NULL && NZV(project->base_path) &&
+			find_cmd_env(VC_COMMAND_DIFF_DIR, TRUE, project->base_path))
+		project_have_vc = TRUE;
 
-	gtk_widget_set_sensitive(menu_vcdiff_file, have_vc && have_file);
-	gtk_widget_set_sensitive(menu_vcdiff_dir, have_vc && have_file);
-	gtk_widget_set_sensitive(menu_vcdiff_project,
-		project != NULL && NZV(project->base_path));
+	gtk_widget_set_sensitive(menu_vcdiff_file, have_vc);
+	gtk_widget_set_sensitive(menu_vcdiff_dir, have_vc);
+	gtk_widget_set_sensitive(menu_vcdiff_project, project_have_vc);
 }