[orca] Filter out dead childNodes

[Joanmarie Diggs <joanied src gnome org>]

commit 3b74abf30fa7ce3925e53411dab2ea2aeac66617
Author: Joanmarie Diggs <jdiggs igalia com>
Date:   Sun Feb 17 20:34:28 2013 -0500

    Filter out dead childNodes

 src/orca/script_utilities.py |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)
---
diff --git a/src/orca/script_utilities.py b/src/orca/script_utilities.py
index 9d90ac8..149dadc 100644
--- a/src/orca/script_utilities.py
+++ b/src/orca/script_utilities.py
@@ -272,7 +272,9 @@ class Utilities:
                 if relation.getRelationType() == \
                         pyatspi.RELATION_NODE_PARENT_OF:
                     for target in range(relation.getNTargets()):
-                        nodes.append(relation.getTarget(target))
+                        node = relation.getTarget(target)
+                        if node and node.getIndexInParent() != -1:
+                            nodes.append(node)
                     return nodes
         except:
             pass