fix 2x1-presenter-zoom layout

conf/vanilla/autoload_configs/conference_layouts.conf.xml

@@ -317,7 +317,7 @@
 	<image x="300" y="300" scale="60"/>
       </layout>
       <layout name="2x1-presenter-zoom" auto-3d-position="true">
-	<image x="0" y="0" scale="180" hscale="360" zoom="true"/>
+	<image x="0" y="0" scale="180" hscale="360" zoom="true" floor="true"/>
 	<image x="180" y="0" scale="180" hscale="360" zoom="true" reservation_id="presenter"/>
       </layout>
       <layout name="presenter-dual-vertical">