diff --git a/ChangeLog b/ChangeLog
index 7624b1d5a..70641a775 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2008-12-06  Wolfgang Lux  <wolfgang.lux@gmail.com>
+
+	* Source/NSDocument.m (-undo:, -redo:, -validateMenuItem:): Move
+	implementation from here ...
+	* Source/NSWindow.m (-undo:, -redo:, -validateMenuItem:): ... to
+	here. Also validate close, miniaturize, and zoom actions.
+
 2008-12-06 Richard Frith-Macdonald <rfm@gnu.org>
 
 	* Source/NSSound.m:
diff --git a/Source/NSDocument.m b/Source/NSDocument.m
index 38044f2e7..0e4bff7eb 100644
--- a/Source/NSDocument.m
+++ b/Source/NSDocument.m
@@ -1319,46 +1319,6 @@ originalContentsURL: (NSURL *)orig
     {
       result = ([self fileName] != nil && [self isDocumentEdited]);
     }
-  else if (sel_eq(action, @selector(undo:)))
-    {
-      if (_undo_manager == nil)
-        {
-          result = NO;
-        }
-      else
-        {
-          if ([_undo_manager canUndo])
-            {
-              [anItem setTitle: [_undo_manager undoMenuItemTitle]];
-              result = YES;
-            }
-          else
-            {
-              [anItem setTitle: [_undo_manager undoMenuTitleForUndoActionName: @""]];
-              result = NO;
-            }
-        }
-    }
-  else if (sel_eq(action, @selector(redo:)))
-    {
-      if (_undo_manager == nil)
-        {
-          result = NO;
-        }
-      else
-        {
-          if ([_undo_manager canRedo])
-            {
-              [anItem setTitle: [_undo_manager redoMenuItemTitle]];
-              result = YES;
-            }
-          else
-            {
-              [anItem setTitle: [_undo_manager redoMenuTitleForUndoActionName: @""]];
-              result = NO;
-            }
-        }
-    }
     
   return result;
 }
@@ -1743,14 +1703,4 @@ originalContentsURL: (NSURL *)orig
   [self updateChangeCount: NSChangeDone];
 }
 
-- (void) undo: (id)sender
-{
-  [[self undoManager] undo];
-}
-
-- (void) redo: (id)sender
-{
-  [[self undoManager] redo];
-}
-
 @end
diff --git a/Source/NSWindow.m b/Source/NSWindow.m
index 12b43afd4..8b6c04634 100644
--- a/Source/NSWindow.m
+++ b/Source/NSWindow.m
@@ -50,6 +50,7 @@
 #include <Foundation/NSSet.h>
 #include <Foundation/NSLock.h>
 #include <Foundation/NSUserDefaults.h>
+#include <Foundation/NSUndoManager.h>
 
 #include "AppKit/NSApplication.h"
 #include "AppKit/NSButton.h"
@@ -2979,6 +2980,16 @@ resetCursorRectsForView(NSView *theView)
     }
 }
 
+- (void) undo: (id)sender
+{
+  [[self undoManager] undo];
+}
+
+- (void) redo: (id)sender
+{
+  [[self undoManager] redo];
+}
+
 /**
    If YES, then the window is released when the close method is called.
  */
@@ -4753,6 +4764,73 @@ current key view.<br />
   _f.displays_when_screen_profile_changes = flag;
 }
 
+/*
+ * Menu item validation
+ */
+
+- (BOOL)validateMenuItem: (NSMenuItem *)anItem
+{
+  BOOL result = YES;
+  SEL  action = [anItem action];
+
+  if (sel_eq(action, @selector(performClose:)))
+    {
+      result = ([self styleMask] & NSClosableWindowMask) ? YES : NO;
+    }
+  else if (sel_eq(action, @selector(performMiniaturize:)))
+    {
+      result = ([self styleMask] & NSMiniaturizableWindowMask) ? YES : NO;
+    }
+  else if (sel_eq(action, @selector(performZoom:)))
+    {
+      result = ([self styleMask] & NSResizableWindowMask) ? YES : NO;
+    }
+  else if (sel_eq(action, @selector(undo:)))
+    {
+      NSUndoManager *undo = [self undoManager];
+      if (undo == nil)
+        {
+          result = NO;
+        }
+      else
+        {
+          if ([undo canUndo])
+            {
+              [anItem setTitle: [undo undoMenuItemTitle]];
+              result = YES;
+            }
+          else
+            {
+              [anItem setTitle: [undo undoMenuTitleForUndoActionName: @""]];
+              result = NO;
+            }
+        }
+    }
+  else if (sel_eq(action, @selector(redo:)))
+    {
+      NSUndoManager *undo = [self undoManager];
+      if (undo == nil)
+        {
+          result = NO;
+        }
+      else
+        {
+          if ([undo canRedo])
+            {
+              [anItem setTitle: [undo redoMenuItemTitle]];
+              result = YES;
+            }
+          else
+            {
+              [anItem setTitle: [undo redoMenuTitleForUndoActionName: @""]];
+              result = NO;
+            }
+        }
+    }
+    
+  return result;
+}
+
 /*
  * Assigning a delegate
  */