Issue #18988: The "Tab" key now works when a word is already autocompleted.

3 files changed, 10 insertions, 7 deletions

diff --git a/Lib/idlelib/AutoComplete.py b/Lib/idlelib/AutoComplete.py
index 929d3581c9..f3660307d3 100644
--- a/Lib/idlelib/AutoComplete.py
+++ b/Lib/idlelib/AutoComplete.py
@@ -160,12 +160,9 @@ class AutoComplete:
         if not comp_lists[0]:
             return
         self.autocompletewindow = self._make_autocomplete_window()
-        self.autocompletewindow.show_window(comp_lists,
-                                            "insert-%dc" % len(comp_start),
-                                            complete,
-                                            mode,
-                                            userWantsWin)
-        return True
+        return not self.autocompletewindow.show_window(
+                comp_lists, "insert-%dc" % len(comp_start),
+                complete, mode, userWantsWin)
 
     def fetch_completions(self, what, mode):
         """Return a pair of lists of completions for something. The first list
diff --git a/Lib/idlelib/AutoCompleteWindow.py b/Lib/idlelib/AutoCompleteWindow.py
index 7787e7034c..f666ea628b 100644
--- a/Lib/idlelib/AutoCompleteWindow.py
+++ b/Lib/idlelib/AutoCompleteWindow.py
@@ -157,13 +157,14 @@ class AutoCompleteWindow:
         self.start = self.widget.get(self.startindex, "insert")
         if complete:
             completed = self._complete_string(self.start)
+            start = self.start
             self._change_start(completed)
             i = self._binary_search(completed)
             if self.completions[i] == completed and \
                (i == len(self.completions)-1 or
                 self.completions[i+1][:len(completed)] != completed):
                 # There is exactly one matching completion
-                return
+                return completed == start
         self.userwantswindow = userWantsWin
         self.lasttypedstart = self.start
 
diff --git a/Misc/NEWS b/Misc/NEWS
index 6f7ede30cc..23035d2acb 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -21,6 +21,11 @@ Tests
   test.support was converted to a package. Regression noticed by Zachary
   Ware.
 
+IDLE
+----
+
+- Issue #18988: The "Tab" key now works when a word is already autocompleted.
+
 
 What's New in Python 3.4.0 Alpha 2?
 ===================================