<?xml version="1.0" encoding="utf-8"?>
<!--
http://bugs.adobe.com/jira/browse/SDK-17143

SDK-17143 - Scroller Keyboard navigation is incorrect if viewport is DataGroup

PageUp/Down keys appear to work in reverse.

This is an unusual case: the Scroller's viewport (a VGroup) that
contains just one item, a DataGroup/VerticalLayout with 26 items.
Presently Vertical,HorizontalLayout don't handle this special case.

This bug report also exposes a similar problem with this special
case in inView(). If there's only one item in the layout, and
it doesn't fit within the ScrollR, then inView should always
return < 1.0.

-->

<Application
    xmlns="http://ns.adobe.com/mxml/2009">
    
    <layout>
        <HorizontalLayout/>
    </layout>

    <Script>
        <![CDATA[

        import flex.skin.DefaultItemRenderer;
        import flex.skin.DefaultComplexItemRenderer;
        import mx.collections.ArrayCollection;
        import flash.display.DisplayObject;
        import flex.graphics.graphicsClasses.GraphicElement;
        
        public function mixItemRendererFunction(item:*):IFactory
        {
            if (item is DisplayObject || item is GraphicElement)
                return new ClassFactory(DefaultComplexItemRenderer);
            else
                return new ClassFactory(DefaultItemRenderer);
        }
        
        private function createDP():void
        {
            dgroup.dataProvider = new ArrayCollection(['A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z']);
        }

        ]]>
    </Script>
        
    <Scroller height="200">
        <VGroup>
            <DataGroup id="dgroup"
                creationComplete="createDP()"
                itemRendererFunction="mixItemRendererFunction">
                <layout>
                    <VerticalLayout/>
                </layout>
            </DataGroup>
        </VGroup>
    </Scroller>

</Application>

Fixed in SVN 3481.

Better, but still incorrect.
UP/DOWN buttons behave like PageUP/PageDown

That is the intended behavior. There's only one item after all, so moving one line up or down is a special case. Conflating it with page up/down seems reasonable to me.