diff --git a/Lib/idlelib/AutoComplete.py b/Lib/idlelib/AutoComplete.py
index 6b5391ba790..e4c1aff3dc9 100644
--- a/Lib/idlelib/AutoComplete.py
+++ b/Lib/idlelib/AutoComplete.py
@@ -143,7 +143,7 @@ def open_completions(self, evalfuncs, complete, userWantsWin, mode=None):
         elif hp.is_in_code() and (not mode or mode==COMPLETE_ATTRIBUTES):
             self._remove_autocomplete_window()
             mode = COMPLETE_ATTRIBUTES
-            while i and curline[i-1] in ID_CHARS or ord(curline[i-1]) > 127:
+            while i and (curline[i-1] in ID_CHARS or ord(curline[i-1]) > 127):
                 i -= 1
             comp_start = curline[i:j]
             if i and curline[i-1] == '.':