[orca] Take ranges into account when panning right

[Joanmarie Diggs <joanied src gnome org>]

commit 3fb3c1ef40dc14112ab80c139cf9a101e17fabc6
Author: Joanmarie Diggs <jdiggs igalia com>
Date:   Tue Apr 28 11:02:05 2020 -0400

    Take ranges into account when panning right

 src/orca/braille.py | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)
---
diff --git a/src/orca/braille.py b/src/orca/braille.py
index b95ef2b17..66f8161a9 100644
--- a/src/orca/braille.py
+++ b/src/orca/braille.py
@@ -1482,7 +1482,9 @@ def panRight(panAmount=0):
 
     oldX = viewport[0]
     if panAmount == 0:
-        panAmount = _displaySize[0]
+        oldStart, oldEnd = _getRangeForOffset(oldX)
+        newStart, newEnd = _getRangeForOffset(oldEnd)
+        panAmount = max(0, min(newStart - oldStart, _displaySize[0]))
 
     if len(_lines) > 0:
         lineNum = viewport[1]