[orca] Braille: Fix panLeft creeping slowly back

[Joanmarie Diggs <joanied src gnome org>]

commit 85aad7cc55be7c6e0ced0fe5ad39c9703198090b
Author: Joanmarie Diggs <jdiggs igalia com>
Date:   Tue Apr 28 12:18:33 2020 -0400

    Braille: Fix panLeft creeping slowly back
    
    There can be multiple ranges on a braille line. When panning back the
    width of the display, we want to move to the range that many cells to
    the left. We were just moving to the previous range.

 src/orca/braille.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/src/orca/braille.py b/src/orca/braille.py
index 66f8161a9..9db6636ca 100644
--- a/src/orca/braille.py
+++ b/src/orca/braille.py
@@ -1463,7 +1463,7 @@ def panLeft(panAmount=0):
     oldX = viewport[0]
     if panAmount == 0:
         oldStart, oldEnd = _getRangeForOffset(oldX)
-        newStart, newEnd = _getRangeForOffset(oldStart - 1)
+        newStart, newEnd = _getRangeForOffset(oldStart - _displaySize[0])
         panAmount = max(0, min(oldStart - newStart, _displaySize[0]))
 
     viewport[0] = max(0, viewport[0] - panAmount)