[Hitcher]

Thanks for the detailed reply mardukL but I did edit my other post to say I'd achieved it another way.

I'll post it here in case it's useful to anyone else.

Add this to the actors list -

xml:
<onclick>SetFocus(99)</onclick>

Which focuses this hidden button which controls the list (the conditions stop it wrapping) -

xml:
<control id="99" type="button">

	<onup>noop</onup>

	<ondown>noop</ondown>

	<onleft condition="!String.IsEmpty(Container(500).ListItemNoWrap(-1).Label)">Control.Move(500,-1)</onleft>

	<onright condition="!String.IsEmpty(Container(500).ListItemNoWrap(1).Label)">Control.Move(500,1)</onright>

	<onback>500</onback>

	<include>HiddenControl</include>

</control>

And the 'slideshow' itself is added at the bottom of window -

xml:
<control type="group">

	<visible>Control.HasFocus(99)</visible>

	<control type="image">

		<include>FullscreenDimensions</include>

		<texture>special://skin/extras/backgrounds/default.png</texture>

	</control>

	<control type="image">

		<width>1920</width>

		<height>1080</height>

		<aspectratio>keep</aspectratio>

		<texture>$INFO[Container(500).ListItem.Icon]</texture>

		<fadetime>200</fadetime>

	</control>

</control>