NSWindow subclass does not draw title bar on second rendering - objective-c

Question

I'm writing some glue GUI code for a scripting language implementation, and need to be able to programmatically create windows and intercept the key and mouse commands on their views. I've subclassed both NSWindow and NSView.
When I open a window for the first time, I get a window with a title bar and controls. If I close this window and open another, the controls and title don't appear in the new window. However, if I click where the controls should be, the new window (with invisible controls) still closes.
Is there something I'm doing in my window initialization that could cause this?
+ (HMSLWindow*)hmslWindowWithTitle:(NSString *)title frame:(NSRect)frame {
HMSLWindow* hmslWindow = [[HMSLWindow alloc]
initWithContentRect: frame
styleMask: NSMiniaturizableWindowMask | NSTitledWindowMask | NSClosableWindowMask
backing: NSBackingStoreBuffered
defer: YES];
hmslWindow.title = [title retain];
[hmslWindow setContentView:[[HMSLView alloc] initWithFrame:frame]];
hmslWindow.delegate = [[HMSLWindowDelegate alloc] init];
[hmslWindow cascadeTopLeftFromPoint:NSZeroPoint];
[hmslWindow makeKeyAndOrderFront:self];
[[HMSLWindow windowDictionary] setObject:hmslWindow forKey:[NSNumber numberWithInteger:hmslWindow.windowNumber]];
return hmslWindow;
}
- (void)close {
[[HMSLWindow windowDictionary]
removeObjectForKey:[NSNumber numberWithInteger:self.windowNumber]];
[self.contentView autorelease];
[self.delegate autorelease];
[self.title autorelease];
[super close];
}
First window:
Second window (contentView with white background is correct, but the titlebar is now empty):