gistfile1.txt

var tempSaveSelections = Nil;

- (void)saveOutlineSelections
{
	var rows = [outlineView selectedRowIndexes],
		dataSet = outlineView._itemsForRows;
		
	tempSaveSelections = [dataSet objectsAtIndexes:rows];

    // add the current selection at the end for later restore
	if([outlineView selectedRow] != CPNotFound)
		tempSaveSelections = [tempSaveSelections arrayByAddingObject:[dataSet objectAtIndex:[outlineView selectedRow]]];
	[outlineView _updateHighlightWithOldRows:rows newRows:[CPIndexSet indexSet]];
}

- (void)restoreOutlineSelections
{
	// build a new index set of all the saved objects but first restore the current selected row
	var newIndexSet = [CPIndexSet indexSet],
		dataSet = outlineView._itemsForRows,
		index = [tempSaveSelections count] -1;
		
	if(index != CPNotFound)
	{	outlineView._selectedRow = [dataSet indexOfObject:[tempSaveSelections objectAtIndex:index]];
		while(index--)
			[newIndexSet addIndex:[dataSet indexOfObject:[tempSaveSelections objectAtIndex:index]]];
	}
	[outlineView _updateHighlightWithOldRows:[CPIndexSet indexSet] newRows:newIndexSet];
 	outlineView._selectedRowIndexes  = newIndexSet;
}


- (void)outlineViewItemWillExpand:sender
{	
	[self saveOutlineSelections];
}

- (void)outlineViewItemDidExpand:sender
{
	[self restoreOutlineSelections];
}

- (void)outlineViewItemWillCollapse:sender
{	
	[self saveOutlineSelections];
}

- (void)outlineViewItemDidCollapse:sender
{
	[self restoreOutlineSelections];
}