At WWDC I was asked how to remove the disclosure triangle in an NSOutlineView. Well, first things first. You can change it with this bit of code in your delegate:

- (void)outlineView:(NSOutlineView *)ov
  willDisplayOutlineCell:(NSButtonCell *)cell
  forTableColumn:(NSTableColumn *)tableColumn
  item:(id)item
{
  [cell setImage:[NSImage imageNamed:@“collapsedglyph.tiff”]];
  [cell setAlternateImage:[NSImage imageNamed:@“expandedglyph.tiff”]];
}

If you want to set it to nil, you will have to create an image that is empty.

–corbin

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