gistfile1.txt

<?xml version="1.0" encoding="utf-8"?>
<mx:NSWindow xmlns:mx="http://www.adobe.com/2006/mxml">
    <mx:stylesheet src="css/main.css" />
    <mx:script language="python">
        @bind foo = [1,2,3]
        @class sourceListItem = [classLoader loadClass: "LeftPaneItemRenderer"]
        
        def sourceListItemClick(item, index):
            if(index == len(foo) - 1):
                return [NSAlert alertWithMessageText: "Last item"]
    </mx:script>
    <mx:NSView class="testView" id="mainView">
        <mx:NSSplitView vertical="yes">
            <mx:NSView id="leftPane">
                <mx:NSSourceList dataSource="{foo}" itemRenderer="{sourceListItem}">
                </mx:NSSourceList>
            </mx:NSView>
            <mx:NSView id="rightPane">
            </mx:NSView>
        </mx:NSSplitView>
    </mx:NSView>
</mx:NSWindow>