A snippet for styling the NSTextfields properly [http://imars.info/styling-nstextfields-cocoa-development/]

styling_nstextfields

- (void)drawWithFrame:(NSRect)cellFrame 
               inView:(NSView *)controlView {

  NSImage *img = [NSImage imageNamed:@"tf"];
  [img drawAtPoint:NSPointFromCGPoint(CGPointMake(0, 0)) 
          fromRect:NSZeroRect 
         operation:NSCompositeSourceOver     
          fraction:1];
  cellFrame.origin.x += 10;
  cellFrame.origin.y += 16;
  [super drawWithFrame:cellFrame inView:controlView];
}
  
- (void)selectWithFrame:(NSRect)aRect inView:(NSView *)controlView 
                 editor:(NSText *)textObj 
               delegate:(id)anObject 
                  start:(NSInteger)selStart 
                 length:(NSInteger)selLength {
  
  aRect.origin.x += 10;
  aRect.origin.y += 16;
  [super selectWithFrame:aRect inView:controlView editor:textObj delegate:anObject start:selStart length:selLength];
}