<p>I have a problem redrawing a custom view in simple cocoa application. Drawing is based on one parameter that is being changed by a simple NSSlider. However, although i implement -setParameter: and -parameter methods and bind slider's value to that parameter in interface builder i cannot seem to make a custom view to redraw itself.</p>

<p>The code that does redrawing is like this:</p>

<pre><code>- (void)setParameter:(int)newParameter {
  parameter = newParamter;
  NSLog(@"Updated parameter: %d", parameter);
  [self setNeedsDisplay:YES];
}
</code></pre>

<p>I DO get the message about setting the new parameter although the view doesn't redraw itself. Any ideas are welcome!</p>

The usual syntax is:
```
[self setNeedsDisplay:YES]
```
, although I would assume that that means the same thing. Are you implementing the
```
- (void)drawRect:(NSRect)rect
```
method, or using the
```
drawRect:
```
method of your superclass?