diff --git a/Foundation/CPKeyValueObserving.j b/Foundation/CPKeyValueObserving.j
index e68657a73..b73563066 100644
--- a/Foundation/CPKeyValueObserving.j
+++ b/Foundation/CPKeyValueObserving.j
@@ -775,7 +775,7 @@ var kvoNewAndOld        = CPKeyValueObservingOptionNew | CPKeyValueObservingOpti
     else
     {
         if (!changes)
-            return;
+            [CPException raise:@"CPKeyValueObservingException" reason:@"'didChange...' message called without prior call of 'willChange...'"];
 
         [changes removeObjectForKey:CPKeyValueChangeNotificationIsPriorKey];
 
diff --git a/Tests/Manual/Bindings/AppController.j b/Tests/Manual/Bindings/AppController.j
index 847e5b9ba..f39a66fe9 100644
--- a/Tests/Manual/Bindings/AppController.j
+++ b/Tests/Manual/Bindings/AppController.j
@@ -78,6 +78,27 @@
     [contentView addSubview:employeesScrollView];
     [contentView addSubview:text];
 
+    var button = [CPButton buttonWithTitle:@"Add Item"];
+
+    [button setFrameOrigin:CGPointMake(500, 30)];
+    [button setTarget:self];
+    [button setAction:@selector(addItem:)];
+    [contentView addSubview:button];
+
+    button = [CPButton buttonWithTitle:@"Insert Item"];
+
+    [button setFrameOrigin:CGPointMake(500, 70)];
+    [button setTarget:self];
+    [button setAction:@selector(insertItem:)];
+    [contentView addSubview:button];
+
+    button = [CPButton buttonWithTitle:@"Remove Item"];
+
+    [button setFrameOrigin:CGPointMake(500, 110)];
+    [button setTarget:self];
+    [button setAction:@selector(removeItem:)];
+    [contentView addSubview:button];
+
     companiesController = [CPArrayController new];
     [companiesController bind:@"contentArray" toObject:companies withKeyPath:@"items" options:nil];
 
@@ -108,4 +129,24 @@
     console.log("\nkeyPath: %s\ncontext: %s\nnew: %s\nold: %s", keyPath, context, [[change valueForKey:CPKeyValueChangeNewKey] description], [[change valueForKey:CPKeyValueChangeOldKey] description]);
 }
 
+- (void)addItem:(id)sender
+{
+    var item = [CPDictionary dictionaryWithObjectsAndKeys:@"Seven Dwarves", @"name", [CPArray arrayWithObjects:@"Sneezy", @"Dopey", @"Sleepy", @"Doc", @"Bashful", @"Happy", @"Grumpy"], @"employees"];
+
+    [companiesController addObject:item];
+}
+
+- (void)insertItem:(id)sender
+{
+    var item = [CPDictionary dictionaryWithObjectsAndKeys:@"Acme Corp", @"name", [CPArray arrayWithObjects:@"Road Runner", @"Wile E. Coyote"], @"employees"];
+
+    [companiesController insertObject:item atArrangedObjectIndex:1];
+}
+
+- (void)removeItem:(id)sender
+{
+    if ([[companiesController arrangedObjects] count])
+       [companiesController removeObjectAtArrangedObjectIndex:0];
+}
+
 @end