Custom View-Based NSOutlineView disclosure?

Question

Is there a simple way to customize the disclosure triangle for expandable items?

I tried removing it and calling [outlineView expandItem:X] when my custom disclosure indicator was clicked, but all the sexy built-in animations didn't work. Is there a trick to enable those animations? I tried [outlineView beginUpdates] but that yielded no results either.

Answer 1

Use the animator:

[[[outlineView] animator] expandItem:xyz]

Answer 2

use - (void)outlineView:(NSOutlineView *)outlineView willDisplayOutlineCell:(id)cell forTableColumn:(NSTableColumn *)tableColumn item:(id)item;