Add :nbstart and :nbclose.
diff --git a/src/undo.c b/src/undo.c
index c042d04..4035466 100644
--- a/src/undo.c
+++ b/src/undo.c
@@ -346,7 +346,7 @@
      * Netbeans defines areas that cannot be modified.  Bail out here when
      * trying to change text in a guarded area.
      */
-    if (usingNetbeans)
+    if (netbeans_active())
     {
 	if (netbeans_is_guarded(top, bot))
 	{