[orca] Don't treat deletions from hidden objects as result of BackSpace command

[Joanmarie Diggs <joanied src gnome org>]

commit 397fa65ad8d0ffcbc94f6e442aa9593e9f495a28
Author: Joanmarie Diggs <jdiggs igalia com>
Date:   Wed May 23 14:18:49 2018 -0700

    Don't treat deletions from hidden objects as result of BackSpace command

 src/orca/script_utilities.py |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/src/orca/script_utilities.py b/src/orca/script_utilities.py
index 4c1627a..a3c0658 100644
--- a/src/orca/script_utilities.py
+++ b/src/orca/script_utilities.py
@@ -4666,6 +4666,9 @@ class Utilities:
         if not event.type.startswith("object:text-changed:delete"):
             return False
 
+        if self.isHidden(event.source):
+            return False
+
         keyString, mods = self.lastKeyAndModifiers()
         if keyString == "BackSpace":
             return True