[orca] Ignore extraneous text-selection-changed event from Gedit

[Joanmarie Diggs <joanied src gnome org>]

commit a2f950415b2a82a59b302401e97132814eec67fb
Author: Joanmarie Diggs <jdiggs igalia com>
Date:   Mon Nov 14 03:08:41 2016 -0500

    Ignore extraneous text-selection-changed event from Gedit

 src/orca/scripts/apps/gedit/script.py |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/src/orca/scripts/apps/gedit/script.py b/src/orca/scripts/apps/gedit/script.py
index 94e4128..db424ed 100644
--- a/src/orca/scripts/apps/gedit/script.py
+++ b/src/orca/scripts/apps/gedit/script.py
@@ -151,6 +151,9 @@ class Script(gtk.Script):
         if not self.utilities.isSearchEntry(orca_state.locusOfFocus, True):
             return
 
+        if not self.utilities.isShowingAndVisible(event.source):
+            return
+
         # To avoid extreme chattiness.
         keyString, mods = self.utilities.lastKeyAndModifiers()
         if keyString in ["BackSpace", "Delete"]: