message: More subtle shadow for autocomplete (mac),
diff: [self setWantsLayer:YES];
  self.layer.masksToBounds = YES;
  self.dropShadow = [[NSShadow alloc] init];
  - [self.dropShadow setShadowColor:[NSColor grayColor]];
  + [self.dropShadow setShadowColor:[[NSColor grayColor]
  + colorWithAlphaComponent:0.7f]];
  [self.dropShadow setShadowOffset:NSMakeSize(0, 5.0)];
  [self.dropShadow setShadowBlurRadius:5.0];
  }
  