diff --git a/Sources/VLDocument.h b/Sources/VLDocument.h
index 83c1243..39a84b8 100644
--- a/Sources/VLDocument.h
+++ b/Sources/VLDocument.h
@@ -26,6 +26,7 @@
 	NSNumber *		songTempo;
 	NSString *		tmpPath;
 	NSFileWrapper *	vcsWrapper;
+	NSMutableArray* observers;
 	int				repeatVolta;
 	bool			brandNew;
 
@@ -59,6 +60,7 @@
 - (void)	   changedFileWrapper;
 - (void)	   willChangeSong;
 - (void)	   didChangeSong;
+- (void)	   addObserver:(id)observer;
 
 @end
 
diff --git a/Sources/VLDocument.mm b/Sources/VLDocument.mm
index 5f253a1..150c5d9 100644
--- a/Sources/VLDocument.mm
+++ b/Sources/VLDocument.mm
@@ -74,6 +74,7 @@
 		vcsWrapper			= nil;
 		repeatVolta			= 2;
 		brandNew			= true;
+		observers			= [[NSMutableArray alloc] init];
 		[self setHasUndoManager:YES];
 		undo				=
 			[[VLKeyValueUndo alloc] initWithOwner:self
@@ -89,6 +90,17 @@
     return self;
 }
 
+- (void) addObserver:(id)observer
+{
+	[observers addObject:observer];
+}
+
+- (void) close
+{
+	[observers makeObjectsPerformSelector:@selector(removeObservers:) withObject:self];
+	[super close];
+}
+
 - (void) dealloc
 {
 	delete song;
@@ -100,7 +112,8 @@
 	[songArranger release];
 	[vcsWrapper release];
 	[undo release];
-	
+	[observers release];
+		
 	if (tmpPath) {
 		[[NSFileManager defaultManager] removeFileAtPath:tmpPath handler:nil];
 		[tmpPath release];
diff --git a/Sources/VLKeyValueUndo.mm b/Sources/VLKeyValueUndo.mm
index e21c0f8..6e1239b 100644
--- a/Sources/VLKeyValueUndo.mm
+++ b/Sources/VLKeyValueUndo.mm
@@ -16,6 +16,7 @@
 	owner			= o;
 	keysAndNames	= [kn retain];
 
+	[owner addObserver:self];
 	for (NSEnumerator * e = [keysAndNames keyEnumerator];
 		 NSString * key = [e nextObject];
 	)
@@ -26,13 +27,16 @@
 	return self;
 }
 
-- (void) dealloc
+- (void)removeObservers:(id)target
 {
 	for (NSEnumerator * e = [keysAndNames keyEnumerator];
 		 NSString * key = [e nextObject];
 	)
-		[owner removeObserver:self forKeyPath:key];
+		[target removeObserver:self forKeyPath:key];
+}
 
+- (void) dealloc
+{
 	[keysAndNames release];
 	[super dealloc];
 }
diff --git a/Sources/VLSheetView.mm b/Sources/VLSheetView.mm
index ec43bb2..5019597 100644
--- a/Sources/VLSheetView.mm
+++ b/Sources/VLSheetView.mm
@@ -891,12 +891,20 @@ static int8_t sSharpAcc[] = {
 
 - (void)awakeFromNib
 {
+	[[self document] addObserver:self];
 	[[self document] addObserver:self forKeyPath:@"song" options:0 context:nil];
 	[[self document] addObserver:self forKeyPath:@"songKey" options:0 context:nil];	
 	[[self document] addObserver:self forKeyPath:@"songGroove" options:0 context:nil];	
 	[self setGrooveMenu:[[self document] valueForKey:@"songGroove"]];
 }
 
+- (void)removeObservers:(id)target
+{
+	[target removeObserver:self forKeyPath:@"song"];
+	[target removeObserver:self forKeyPath:@"songKey"];	
+	[target removeObserver:self forKeyPath:@"songGroove"];	
+}
+
 - (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)o change:(NSDictionary *)c context:(id)ctx
 {
 	if ([keyPath isEqual:@"songKey"]) {