title: NSScrollView jumping to bottom on scroll
body: <p>I have an NSScrollView containing an NSImageView, which resizes based on various factors. When it resizes I have generally changed the image, so I scroll the NSScrollView to the top. This works fine. However, when I start to scroll the NSScrollView again, it moves a few pixels and then (most of the time) jumps to the bottom of the scroll. After it jumps once, it works as normal until I move the scroller to the top again. This is driving me insane. All I'm really doing is this:</p>
  
  <pre><code>[_imageView setImage: anNSImage];
  
  NSRect frame;
  
  NSSize imageSize = [anNSImage] size];
  frame.size = imageSize;
  frame.origin = NSZeroPoint;
  
  [_imageView setFrame: frame];
  [[_mainScrollview contentView] scrollToPoint: NSMakePoint(0, [_imageView frame].size.height - [_mainScrollview frame].size.height)];
  </code></pre>