diff --git a/AppKit/CPApplication.j b/AppKit/CPApplication.j
index f3783c75a..90d87c5c3 100644
--- a/AppKit/CPApplication.j
+++ b/AppKit/CPApplication.j
@@ -986,7 +986,9 @@ var CPMainCibFile               = @"CPMainCibFile",
         return;
     }
 
-    [aSheet._windowView _enableSheet:YES inWindow:aWindow];
+    if (![aWindow attachedSheet])
+        [aSheet._windowView _enableSheet:YES inWindow:aWindow];
+
     [aWindow _attachSheet:aSheet modalDelegate:aModalDelegate didEndSelector:didEndSelector contextInfo:contextInfo];
 }
 
diff --git a/AppKit/CPWindow/CPWindow.j b/AppKit/CPWindow/CPWindow.j
index f770fc642..baafd32a4 100644
--- a/AppKit/CPWindow/CPWindow.j
+++ b/AppKit/CPWindow/CPWindow.j
@@ -2679,6 +2679,23 @@ CPTexturedBackgroundWindowMask
     [attachedSheet setFrame:sheetFrame display:YES animate:NO];
 }
 
+- (void)_previousSheetIsClosedNotification:(CPNotification)aNotification
+{
+    [[CPNotificationCenter defaultCenter] removeObserver:self name:CPWindowDidEndSheetNotification object:self];
+
+    var sheet = _sheetContext[@"nextSheet"],
+        modalDelegate =_sheetContext[@"nextModalDelegate"],
+        endSelector = _sheetContext[@"nextEndSelector"],
+        contextInfo = _sheetContext[@"nextContextInfo"];
+
+    // Needed, becauwe when the notification CPWindowDidEndSheetNotification is sent, the sheetContext is not up to date...
+    setTimeout(function()
+    {
+        [sheet._windowView _enableSheet:YES inWindow:self];
+        [self _attachSheet:sheet modalDelegate:modalDelegate didEndSelector:endSelector contextInfo:contextInfo];
+    }, 0)
+}
+
 /*
     Starting point for sheet session, called from CPApplication beginSheet:
 */
@@ -2687,9 +2704,24 @@ CPTexturedBackgroundWindowMask
 {
     if (_sheetContext)
     {
-        [CPException raise:CPInternalInconsistencyException
-            reason:@"The target window of beginSheet: already has a sheet, did you forget orderOut: ?"];
-        return;
+        // Here we wait till the current sheet is closed
+        if (_sheetContext[@"isClosing"])
+        {
+            // Here we save the next sheet to open
+            _sheetContext[@"nextSheet"] = aSheet;
+            _sheetContext[@"nextModalDelegate"] = aModalDelegate;
+            _sheetContext[@"nextEndSelector"] = didEndSelector;
+            _sheetContext[@"nextContextInfo"] = contextInfo;
+
+            [[CPNotificationCenter defaultCenter] addObserver:self selector:@selector(_previousSheetIsClosedNotification:) name:CPWindowDidEndSheetNotification object:self];
+            return;
+        }
+        else
+        {
+            [CPException raise:CPInternalInconsistencyException
+                reason:@"The target window of beginSheet: already has a sheet, did you forget orderOut: ?"];
+            return;
+        }
     }
 
     _sheetContext = {
@@ -2741,7 +2773,12 @@ CPTexturedBackgroundWindowMask
 */
 - (void)_detachSheetWindow
 {
+    if (_sheetContext["isClosing"])
+        return;
+
     _sheetContext["isAttached"] = NO;
+    _sheetContext["isClosing"] = YES;
+    _sheetContext["opened"] = NO;
 
     // A timer seems to be necessary for the animation to work correctly.
     // It would be ideal to block here and spin the event loop, until attach is complete.
@@ -2874,12 +2911,6 @@ CPTexturedBackgroundWindowMask
         return;
     }
 
-    if (_sheetContext["isClosing"])
-        return;
-
-    _sheetContext["opened"] = NO;
-    _sheetContext["isClosing"] = YES;
-
     // The parent window can be orderedOut to disable the sheet animate out, as in Cocoa
     if ([self isVisible])
     {
diff --git a/Tests/Manual/AttachedSheet2/SheetWindowController.j b/Tests/Manual/AttachedSheet2/SheetWindowController.j
index 096beec68..41866b38f 100644
--- a/Tests/Manual/AttachedSheet2/SheetWindowController.j
+++ b/Tests/Manual/AttachedSheet2/SheetWindowController.j
@@ -399,9 +399,6 @@
 
     _returnCode = 77;
     [CPApp endSheet:[self window] returnCode:_returnCode];
-
-    if (orderOutAfter)
-        [[self window] orderOut:nil];
 }
 
 //
@@ -519,7 +516,15 @@
     // test sheet chaining. it should be possible to start another sheet from didEndSheet,
     // but only if we orderOut: the sheet before we called endSheet: This is how cocoa works too.
     if (returnCode == 77)
+    {
+        var orderOutAfter = [_orderOutAfterCheckbox state];
+
+        if (orderOutAfter)
+            [[self window] orderOut:self];
+
         [self runSheetForWindow:parentWindow];
+    }
+
         //[self runAlertSheet:parentWindow];
 }