I'm trying to implement an `NSOutlineView` with multiple-line cells.

Following advice from this and other sites, I have come up with the following code in the view's delegate.

```
- (CGFloat)outlineView:(NSOutlineView *)outlineView heightOfRowByItem:(id)item {
    NSTableColumn *column = [outlineView outlineTableColumn];
    NSCell *cell = [column dataCell];

    [cell setStringValue:[item valueForKey:@"label"]];

    return [cell cellSizeForBounds:NSMakeRect(0.0, 0.0, [column width], CGFLOAT_MAX)].height;
}

```

The cell in the outline table column is set to wrap.

I get, however, a strange graphical behavior—the text lines overlap, as seen in <http://screencast.com/t/ewJUwRmlGZqh>. It seems like the cell is getting the right size, but not pushing down the underlying cells.

Could someone help me?