diff --git a/AppKit/CPView.j b/AppKit/CPView.j
index ae8aeb595..e67dd263b 100644
--- a/AppKit/CPView.j
+++ b/AppKit/CPView.j
@@ -238,6 +238,11 @@ var CPViewFlags                     = { },
     return [CPSet setWithObjects:@"frameOrigin", @"frameSize"];
 }
 
++ (CPSet)keyPathsForValuesAffectingBounds
+{
+    return [CPSet setWithObjects:@"boundsOrigin", @"boundsSize"];
+}
+
 - (id)init
 {
     return [self initWithFrame:CGRectMakeZero()];
@@ -308,7 +313,7 @@ var CPViewFlags                     = { },
 */
 - (CPArray)subviews
 {
-    return _subviews;
+    return [_subviews copy];
 }
 
 /*!
@@ -441,7 +446,7 @@ var CPViewFlags                     = { },
 
     [_superview willRemoveSubview:self];
     
-    [[_superview subviews] removeObject:self];
+    [_superview._subviews removeObject:self];
 
 #if PLATFORM(DOM)
         CPDOMDisplayServerRemoveChild(_superview._DOMElement, _DOMElement);
@@ -468,6 +473,73 @@ var CPViewFlags                     = { },
     [self _insertSubview:aView atIndex:index];
 }
 
+- (void)setSubviews:(CPArray)newSubviews
+{
+    if (!newSubviews)
+        [CPException raise:CPInvalidArgumentException reason:"newSubviews cannot be nil in -[CPView setSubviews:]"];
+
+    // Trivial Case 0: Same array somehow
+    if ([_subviews isEqual:newSubviews])
+        return;
+
+    // Trivial Case 1: No current subviews, simply add all new subviews.
+    if ([_subviews count] === 0)
+    {
+        var index = 0,
+            count = [newSubviews count];
+
+        for (; index < count; ++index)
+            [self addSubview:newSubviews[index]];
+
+        return;
+    }
+
+    // Trivial Case 2: No new subviews, simply remove all current subviews.
+    if ([newSubviews count] === 0)
+    {
+        var count = [subviews count];
+
+        while (count--)
+            [_subviews[count] removeFromSuperview];
+
+        return;
+    }
+
+    // Find out the views that were removed.
+    var removedSubviews = [CPMutableSet setWithArray:_subviews];
+
+    [removedSubviews removeObjectsInArray:newSubviews];
+    [removedSubviews makeObjectsPerformSelector:@selector(removeFromSuperview)];
+
+    // Find out which views need to be added.
+    var addedSubviews = [CPMutableSet setWithArray:newSubviews];
+
+    [addedSubviews removeObjectsInArray:_subviews];
+
+    var addedSubview = nil,
+        addedSubviewEnumerator = [addedSubviews objectEnumerator];
+
+    while (addedSubview = [addedSubviewEnumerator nextObject])
+        [self addSubview:addedSubview];
+
+    // If the order is fine, no need to reorder.
+    if ([_subviews isEqual:newSubviews])
+        return;
+
+    _subviews = [newSubviews copy];
+
+    var index = 0,
+        count = [_subviews count];
+
+    for (; index < count; ++index)
+    {
+        var subview = _subviews[index];
+
+        CPDOMDisplayServerRemoveChild(_DOMElement, subview._DOMElement);
+        CPDOMDisplayServerAppendChild(_DOMElement, subview._DOMElement);
+    }
+}
+
 /* @ignore */
 - (void)_setWindow:(CPWindow)aWindow
 {
@@ -816,6 +888,16 @@ var CPViewFlags                     = { },
     return _CGRectMakeCopy(_bounds);
 }
 
+- (CGPoint)boundsOrigin
+{
+    return _CGPointMakeCopy(_bounds.origin);
+}
+
+- (CGSize)boundsSize
+{
+    return _CGSizeMakeCopy(_bounds.size);
+}
+
 /*!
     Sets the location of the receiver inside its frame. The method
     posts a CPViewBoundsDidChangeNotification to the
@@ -1863,12 +1945,11 @@ setBoundsOrigin:
 
 - (BOOL)performKeyEquivalent:(CPEvent)anEvent
 {
-    var subviews = [self subviews],
-        count = [subviews count];
+    var count = [_subviews count];
 
     // Is reverse iteration correct here? It matches the other (correct) code like hit testing.
     while (count--)
-        if ([subviews[count] performKeyEquivalent:anEvent])
+        if ([_subviews[count] performKeyEquivalent:anEvent])
             return YES;
 
     return NO;
diff --git a/AppKit/CPWindow/CPWindow.j b/AppKit/CPWindow/CPWindow.j
index c3f1fe0db..59f1c8c20 100644
--- a/AppKit/CPWindow/CPWindow.j
+++ b/AppKit/CPWindow/CPWindow.j
@@ -1999,7 +1999,8 @@ CPTexturedBackgroundWindowMask
 
 - (void)_setUpMasksForView:(CPView)aView
 {
-    var views = [CPArray arrayWithArray:[aView subviews]];
+    var views = [aView subviews];
+
     [views addObject:aView];
     
     for (var i = 0, count = [views count]; i < count; i++)
@@ -2014,7 +2015,8 @@ CPTexturedBackgroundWindowMask
 
 - (void)_restoreMasksForView:(CPView)aView
 {
-    var views = [CPArray arrayWithArray:[aView subviews]];
+    var views = [aView subviews];
+
     [views addObject:aView];
     
     for (var i = 0, count = [views count]; i < count; i++)
diff --git a/AppKit/Cib/_CPCibCustomView.j b/AppKit/Cib/_CPCibCustomView.j
index 808cf85fc..e50f0cb58 100644
--- a/AppKit/Cib/_CPCibCustomView.j
+++ b/AppKit/Cib/_CPCibCustomView.j
@@ -37,7 +37,13 @@
 
 - (void)setCustomClassName:(CPString)aClassName
 {
+    if (_className === aClassName)
+        return;
+
     _className = aClassName;
+
+    [self setNeedsDisplay:YES];
+    [self setNeedsLayout];
 }
 
 @end
@@ -97,9 +103,7 @@ var _CPCibCustomViewClassNameKey    = @"_CPCibCustomViewClassNameKey";
         [view setBounds:[self bounds]];
         
         // Since the object replacement logic hasn't had a chance to kick in yet, we need to do it manually:
-        
-        // we need to copy subviews since each time we add a subview to a different view its removed from the original subviews array
-        var subviews = [[self subviews] copy],
+        var subviews = [self subviews],
             index = 0,
             count = subviews.length;
         
diff --git a/AppKit/Platform/CPPlatformWindow.j b/AppKit/Platform/CPPlatformWindow.j
index 7c665e9bf..fa1917281 100644
--- a/AppKit/Platform/CPPlatformWindow.j
+++ b/AppKit/Platform/CPPlatformWindow.j
@@ -104,7 +104,7 @@ var PrimaryPlatformWindow   = NULL;
 
     frame.origin = CGPointMakeZero();
 
-    if ([CPMenu menuBarVisible])
+    if ([CPMenu menuBarVisible] && [CPPlatformWindow primaryPlatformWindow] === self)
     {
         var menuBarHeight = [[CPApp mainMenu] menuBarHeight];
 
diff --git a/Foundation/CPObject.j b/Foundation/CPObject.j
index d8e90512c..70a5bc23d 100644
--- a/Foundation/CPObject.j
+++ b/Foundation/CPObject.j
@@ -470,12 +470,12 @@ CPLog(@"Got some class: %@", inst);
     return [self UID];
 }
 
-- (unsigned)UID
+- (CPString)UID
 {
     if (typeof self.__address === "undefined")
         self.__address = _objj_generateObjectHash();
 
-    return __address;
+    return __address + "";
 }
 
 /*!