diff --git a/Lib/idlelib/AutoCompleteWindow.py b/Lib/idlelib/AutoCompleteWindow.py
index 05cd42a..dfe5f30 100644
--- a/Lib/idlelib/AutoCompleteWindow.py
+++ b/Lib/idlelib/AutoCompleteWindow.py
@@ -10,13 +10,14 @@
 KEYPRESS_VIRTUAL_EVENT_NAME = "<<autocompletewindow-keypress>>"
 # We need to bind event beyond <Key> so that the function will be called
 # before the default specific IDLE function
-KEYPRESS_SEQUENCES = ("<Key>", "<Key-BackSpace>", "<Key-Return>",
-                      "<Key-Up>", "<Key-Down>", "<Key-Home>", "<Key-End>")
+KEYPRESS_SEQUENCES = ("<Key>", "<Key-BackSpace>", "<Key-Return>", "<Key-Tab>",
+                      "<Key-Up>", "<Key-Down>", "<Key-Home>", "<Key-End>",
+                      "<Key-Prior>", "<Key-Next>")
 KEYRELEASE_VIRTUAL_EVENT_NAME = "<<autocompletewindow-keyrelease>>"
 KEYRELEASE_SEQUENCE = "<KeyRelease>"
-LISTUPDATE_SEQUENCE = "<ButtonRelease>"
+LISTUPDATE_SEQUENCE = "<B1-ButtonRelease>"
 WINCONFIG_SEQUENCE = "<Configure>"
-DOUBLECLICK_SEQUENCE = "<Double-ButtonRelease>"
+DOUBLECLICK_SEQUENCE = "<B1-Double-ButtonRelease>"
 
 class AutoCompleteWindow:
 
@@ -49,6 +50,8 @@
         # event ids
         self.hideid = self.keypressid = self.listupdateid = self.winconfigid \
         = self.keyreleaseid = self.doubleclickid                         = None
+        # Flag set if last keypress was a tab
+        self.lastkey_was_tab = False
 
     def _change_start(self, newstart):
         i = 0
@@ -118,11 +121,6 @@
             i = 0
             while i < len(lts) and i < len(selstart) and lts[i] == selstart[i]:
                 i += 1
-            previous_completion = self.completions[cursel - 1]
-            while cursel > 0 and selstart[:i] <= previous_completion:
-                i += 1
-                if selstart == previous_completion:
-                    break  # maybe we have a duplicate?
             newstart = selstart[:i]
         self._change_start(newstart)
 
@@ -206,7 +204,7 @@
                                              self.keyrelease_event)
         self.widget.event_add(KEYRELEASE_VIRTUAL_EVENT_NAME,KEYRELEASE_SEQUENCE)
         self.listupdateid = listbox.bind(LISTUPDATE_SEQUENCE,
-                                         self.listupdate_event)
+                                         self.listselect_event)
         self.winconfigid = acw.bind(WINCONFIG_SEQUENCE, self.winconfig_event)
         self.doubleclickid = listbox.bind(DOUBLECLICK_SEQUENCE,
                                           self.doubleclick_event)
@@ -237,11 +235,12 @@
             return
         self.hide_window()
 
-    def listupdate_event(self, event):
+    def listselect_event(self, event):
         if not self.is_active():
             return
         self.userwantswindow = True
-        self._selection_changed()
+        cursel = int(self.listbox.curselection()[0])
+        self._change_start(self.completions[cursel])
 
     def doubleclick_event(self, event):
         # Put the selected completion in the text, and close the list
@@ -257,7 +256,8 @@
             state = event.mc_state
         else:
             state = 0
-
+        if keysym != "Tab":
+            self.lastkey_was_tab = False
         if (len(keysym) == 1 or keysym in ("underscore", "BackSpace")
             or (self.mode==AutoComplete.COMPLETE_FILES and keysym in
                 ("period", "minus"))) \
@@ -339,13 +339,21 @@
             self.listbox.select_clear(cursel)
             self.listbox.select_set(newsel)
             self._selection_changed()
+            self._change_start(self.completions[newsel])
             return "break"
 
         elif (keysym == "Tab" and not state):
-            # The user wants a completion, but it is handled by AutoComplete
-            # (not AutoCompleteWindow), so ignore.
-            self.userwantswindow = True
-            return
+            if self.lastkey_was_tab:
+                # two tabs in a row; insert current selection and close acw
+                cursel = int(self.listbox.curselection()[0])
+                self._change_start(self.completions[cursel])
+                self.hide_window()
+                return "break"
+            else:
+                # first tab; let AutoComplete handle the completion
+                self.userwantswindow = True
+                self.lastkey_was_tab = True
+                return
 
         elif reduce(lambda x, y: x or y,
                     [keysym.find(s) != -1 for s in ("Shift", "Control", "Alt",
diff --git a/Lib/idlelib/NEWS.txt b/Lib/idlelib/NEWS.txt
index 52c7f00..86802ff 100644
--- a/Lib/idlelib/NEWS.txt
+++ b/Lib/idlelib/NEWS.txt
@@ -3,6 +3,11 @@
 
 *Release date: XX-XXX-200X*
 
+- Corrected some bugs in AutoComplete.  Also, Page Up/Down in ACW implemented;
+  mouse and cursor selection in ACWindow implemented; double Tab inserts
+  current selection and closes ACW (similar to double-click and Return); scroll
+  wheel now works in ACW.  Added AutoComplete instructions to IDLE Help.
+
 - AutoCompleteWindow moved below input line, will move above if there
   isn't enough space.  Patch 1621265 Tal Einat
 
diff --git a/Lib/idlelib/help.txt b/Lib/idlelib/help.txt
index 6d2ba2f..76cccf0 100644
--- a/Lib/idlelib/help.txt
+++ b/Lib/idlelib/help.txt
@@ -44,6 +44,10 @@
 	Find in Files... -- Open a search dialog box for searching files
 	Replace...       -- Open a search-and-replace dialog box
 	Go to Line       -- Ask for a line number and show that line
+	Show Calltip     -- Open a small window with function param hints
+	Show Completions -- Open a scroll window allowing selection keywords
+			    and attributes. (see '*TIPS*', below)
+	Show Parens	 -- Highlight the surrounding parenthesis
 	Expand Word      -- Expand the word you have typed to match another
 		            word in the same buffer; repeat to get a
                             different expansion
@@ -91,6 +95,7 @@
 	Code Context --	  Open a pane at the top of the edit window which
 			  shows the block context of the section of code
 			  which is scrolling off the top or the window.
+			  (Not present in Shell window.)
 
 Windows Menu:
 
@@ -138,8 +143,11 @@
 	Control-left/right Arrow moves by words in a strange but useful way.
 	Home/End go to begin/end of line.
 	Control-Home/End go to begin/end of file.
-	Some useful Emacs bindings (Control-a, Control-e, Control-k, etc.)
-		are inherited from Tcl/Tk.
+	Some useful Emacs bindings are inherited from Tcl/Tk:
+		Control-a     beginning of line
+		Control-e     end of line
+		Control-k     kill line (but doesn't put it in clipboard)
+		Control-l     center window around the insertion point
 	Standard Windows bindings may work on that platform.
 	Keybindings are selected in the Settings Dialog, look there.
 
@@ -155,6 +163,52 @@
 
         See also the indent/dedent region commands in the edit menu.
 
+Completions:
+
+	Completions are supplied for functions, classes, and attributes of
+	classes, both built-in and user-defined.  Completions are also provided
+	for filenames.
+
+	The AutoCompleteWindow (ACW) will open after a predefined delay
+	(default is two seconds) after a '.' or (in a string) an os.sep is
+	typed.  If after one of those characters (plus zero or more other
+	characters) you type a Tab the ACW will open immediately if a possible
+	continuation is found.
+
+	If there is only one possible completion for the characters entered, a
+	Tab will supply that completion without opening the ACW.
+
+	'Show Completions' will force open a completions window.  In an empty
+	string, this will contain the files in the current directory.  On a
+	blank line, it will contain the built-in and user-defined functions and
+	classes in the current name spaces, plus any modules imported.  If some
+	characters have been entered, the ACW will attempt to be more specific.
+
+	If string of characters is typed, the ACW selection will jump to the
+	entry most closely matching those characters. Entering a Tab will cause
+	the longest non-ambiguous match to be entered in the Edit window or
+	Shell.  Two Tabs in a row will supply the current ACW selection, as
+	will Return or a double click.  Cursor keys, Page Up/Down, mouse
+	selection, and the scrollwheel all operate on the ACW.
+
+	'Hidden' attributes can be accessed by typing the beginning of hidden
+	name after a '.'.  e.g. '_'.  This allows access to modules with
+	'__all__' set, or to class-private attributes.
+
+	Completions and the 'Expand Word' facility can save a lot of typing!
+
+	Completions are currently limited to those in the namespaces.  Names in
+	an Edit window which are not via __main__ or sys.modules will not be
+	found.  Run the module once with your imports to correct this
+	situation.  Note that IDLE itself places quite a few modules in
+	sys.modules, so much can be found by default, e.g. the re module.
+
+	If you don't like the ACW popping up unbidden, simply make the delay
+	longer or disable the extension.  OTOH, you could make the delay zero.
+
+	You could also switch off the CallTips extension.  (We will be adding
+	a delay to the call tip window.)
+
 Python Shell window:
 
 	Control-c interrupts executing command.
@@ -165,7 +219,7 @@
 
 	Alt-p retrieves previous command matching what you have typed.
 	Alt-n retrieves next.
-	      (These are Control-p, Control-n on the Mac)      
+	      (These are Control-p, Control-n on the Mac)
 	Return while cursor is on a previous command retrieves that command.
 	Expand word is also useful to reduce typing.
 
@@ -196,7 +250,7 @@
 	be changed using the Settings dialog.
 
 Command line usage:
-	
+
 	Enter idle -h at the command prompt to get a usage message.
 
 Running without a subprocess:
@@ -211,3 +265,18 @@
 	re-import any specific items (e.g. from foo import baz) if the changes
 	are to take effect.  For these reasons, it is preferable to run IDLE
 	with the default subprocess if at all possible.
+
+Extensions:
+
+	IDLE contains an extension facility.  See the beginning of
+	config-extensions.def in the idlelib directory for further information.
+	The default extensions are currently:
+
+		FormatParagraph
+		AutoExpand
+		ZoomHeight
+		ScriptBinding
+		CallTips
+		ParenMatch
+		AutoComplete
+		CodeContext