diff --git a/src/sas/qtgui/Utilities/CodeEditor.py b/src/sas/qtgui/Utilities/CodeEditor.py
index 4ed3211839..19da75ccf1 100644
--- a/src/sas/qtgui/Utilities/CodeEditor.py
+++ b/src/sas/qtgui/Utilities/CodeEditor.py
@@ -34,7 +34,7 @@ def lineNumberAreaWidth(self):
             digits += 1
         # line number display width padded with extra pixels.
         # Chosen to "look nice", hence magic numbers
-        space = 3 + self.fontMetrics().width('9') * digits
+        space = 3 + self.fontMetrics().new_width('9') * digits
         return space
 
     def updateLineNumberAreaWidth(self):