add get-client-handle' to window<%>'

original commit: 81cbf1ae1fb81bce7eb0aa8637a2656797bdb6f1

collects/mred/private/mrtop.rkt

@@ -139,6 +139,8 @@
         [do-set-status-text (lambda (s)
                               (when status-message
                                 (send status-message set-label s)))])
+      (override
+        [get-client-handle (lambda () (send wx-panel get-client-handle))])
       (sequence 
 	(super-init (lambda () (set! wx (mk-wx finish)) wx) 
                     (lambda () wx-panel) (lambda () mid-panel)

collects/mred/private/mrwindow.rkt

@@ -116,7 +116,7 @@
       get-client-size get-size get-width get-height get-x get-y
       get-cursor set-cursor popup-menu
       show is-shown? on-superwindow-show refresh
-      get-handle))
+      get-handle get-client-handle))
 
   (define-keywords window%-keywords [enabled #t])
 
@@ -173,6 +173,7 @@
 	[get-plain-label (lambda () (and (string? label) (wx:label->plain-label label)))]
 
 	[get-handle (lambda () (send wx get-handle))]
+	[get-client-handle (lambda () (send wx get-client-handle))]
 
 	[accept-drop-files
 	 (entry-point

collects/mred/private/wx/cocoa/window.rkt

@@ -727,6 +727,7 @@
       (send (get-parent) end-no-cursor-rects))
 
     (define/public (get-handle) (get-cocoa))
+    (define/public (get-client-handle) (get-cocoa-content))
 
     (define/public (popup-menu m x y)
       (send m do-popup (get-cocoa-content) (get-cocoa-window) x (flip-client y)

collects/mred/private/wx/gtk/window.rkt

@@ -612,6 +612,7 @@
     (define/public (on-drop-file path) (void))
 
     (define/public (get-handle) (get-gtk))
+    (define/public (get-client-handle) (get-client-gtk))
 
     (define/public (popup-menu m x y)
       (let ([gx (box x)]

collects/mred/private/wx/win32/window.rkt

@@ -249,6 +249,7 @@
   (define/public (on-set-focus) (void))
   (define/public (on-kill-focus) (void))
   (define/public (get-handle) hwnd)
+  (define/public (get-client-handle) (get-client-hwnd))
 
   (define enabled? #t)
   (define parent-enabled? #t)

collects/scribblings/gui/window-intf.scrbl

@@ -81,6 +81,25 @@ Note that under X, keyboard focus can move to the menu bar
 }
 
 
+@defmethod[(get-client-handle) cpointer?]{
+
+Returns a handle to the ``inside'' of the window for the current
+platform's GUI toolbox. The value that the pointer represents depends
+on the platform:
+
+@itemize[
+
+ @item{Windows: @tt{HWND}}
+
+ @item{Mac OS X: @tt{NSView}}
+
+ @item{X: @tt{GtkWidget}}
+
+]
+
+See also @method[window<%> get-handle].}
+
+
 @defmethod[(get-client-size)
            (values (integer-in 0 10000)
                    (integer-in 0 10000))]{
@@ -107,9 +126,10 @@ Returns the window's cursor, or @scheme[#f] if this window's cursor
 
 }
 
+
 @defmethod[(get-handle) cpointer?]{
 
-Returns a handle to the window for the current platform's GUI
+Returns a handle to the ``outside'' of the window for the current platform's GUI
 toolbox. The value that the pointer represents depends on the
 platform:
 
@@ -124,7 +144,7 @@ platform:
 
 ]
 
-}
+See also @method[window<%> get-client-handle].}
 
 
 @defmethod[(get-height)