Improved panel presenting

- you can now present a new modal panel right after dismissing a previous one.

Core/Source/OSX/NSWindowController+DTPanelControllerPresenting.m

@@ -16,13 +16,12 @@ @implementation NSWindowController (DTPanelControllerPresenting)
 
 #pragma mark - Private Methods
 
-// called as a result of the sheed ending notification
-- (void)_didFinishDismissingPanel:(NSNotification *)notification
+// called as a result of the sheed ending
+- (void)_didFinishDismissingSheet:(NSWindow *)sheet returnCode:(NSInteger)returnCode contextInfo:(void *)contextInfo;
 {
-	// remove notification
-	[[NSNotificationCenter defaultCenter] removeObserver:self name:NSWindowDidEndSheetNotification object:self.window];
+	NSAssert(contextInfo == &DTPresentedViewControllerDismissalQueueKey, @"Incorrect context info");
 
-	// dismiss the panel controller
+	// release the panel controller
 	objc_setAssociatedObject(self, &DTPresentedViewControllerDismissalQueueKey, nil, OBJC_ASSOCIATION_RETAIN);
 }
 
@@ -37,11 +36,12 @@ - (void)presentModalPanelController:(NSWindowController *)panelController
 		NSLog(@"Already presenting %@, cannot modally present another panel", NSStringFromClass([windowController class]));
 		return;
 	}
-
-	[NSApp beginSheet:panelController.window modalForWindow:self.window modalDelegate:nil didEndSelector:nil contextInfo:nil];
-
+
 	// retain the panel view controller
 	objc_setAssociatedObject(self, &DTPresentedViewControllerKey, panelController, OBJC_ASSOCIATION_RETAIN);
+
+	// begin the sheet and set our own custom didEndElector which frees the controller
+	[NSApp beginSheet:panelController.window modalForWindow:self.window modalDelegate:self didEndSelector:@selector(_didFinishDismissingSheet:returnCode:contextInfo:) contextInfo:&DTPresentedViewControllerDismissalQueueKey];
 }
 
 - (void)dismissModalPanelController
@@ -57,14 +57,11 @@ - (void)dismissModalPanelController
 	// retain it in the dismissal queue so that we can present a new one right after the out animation has finished
 	objc_setAssociatedObject(self, &DTPresentedViewControllerDismissalQueueKey, windowController, OBJC_ASSOCIATION_RETAIN);
 
-	// get notified if panel has been dismissed
-	[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(_didFinishDismissingPanel:) name:NSWindowDidEndSheetNotification object:self.window];
-
 	// dismiss the panel
 	[windowController.window close];
 	[NSApp endSheet:windowController.window];
 
-	// free the reference
+	// free the controller reference
 	objc_setAssociatedObject(self, &DTPresentedViewControllerKey, nil, OBJC_ASSOCIATION_RETAIN);
 }