[orca] Don't update the current mouse review object if we didn't present anything

[Joanmarie Diggs <joanied src gnome org>]

commit 246ca77ba155026648e075161ebcc17d7c15b89a
Author: Joanmarie Diggs <jdiggs igalia com>
Date:   Mon Jul 8 14:35:14 2019 -0400

    Don't update the current mouse review object if we didn't present anything

 src/orca/mouse_review.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/src/orca/mouse_review.py b/src/orca/mouse_review.py
index d91032d40..d00e49dc9 100644
--- a/src/orca/mouse_review.py
+++ b/src/orca/mouse_review.py
@@ -442,8 +442,8 @@ class MouseReviewer:
             obj = pyatspi.findAncestor(obj, isRow) or obj
 
         new = _ItemContext(pX, pY, obj, window, script)
-        new.present(self._currentMouseOver)
-        self._currentMouseOver = new
+        if new.present(self._currentMouseOver):
+            self._currentMouseOver = new
 
     def _listener(self, event):
         """Generic listener, mainly to output debugging info."""