when I throw together a test app in gorm, the NSTextView does not
behave as I would expect, although it works okay from code like this:

  NSScrollView *textScrollView = [[NSScrollView alloc] initWithFrame: mRect];
  [textScrollView setBorderType: NSBezelBorder];
  [textScrollView setHasHorizontalScroller: NO];
  [textScrollView setHasVerticalScroller: YES];
  [textScrollView setAutoresizingMask: NSViewHeightSizable|NSViewWidthSizable];

  mRect = [[textScrollView contentView] frame];
  NSTextView *textView = [[NSTextView alloc] init];
  [textView setFrame: mRect];
  [textView setTextContainerInset: NSMakeSize(5,5)];
  [textView setBackgroundColor: [NSColor textBackgroundColor]];
  [textView setRichText: YES];
  [textView setUsesFontPanel: YES];
  [textView setHorizontallyResizable: NO];
  [textView setVerticallyResizable: YES];
  [textView setMinSize: NSMakeSize (0, 0)];
  [textView setMaxSize: NSMakeSize (1E7, 1E7)];
  [textView setAutoresizingMask: NSViewHeightSizable|NSViewWidthSizable];
  [[textView textContainer] setContainerSize: NSMakeSize (mRect.size.width, 1E7)];

  [[textView textContainer] setWidthTracksTextView: YES];
  [textView setString: @""];

  [textScrollView setDocumentView: textView];

  [[myWindow contentView] addSubview: textScrollView];

(code from GNUmail)

instead it grows when resized horizontally but will not shrink back.

see attached tgz for demo of problem + screenshot