+<!ELEMENT Panel (Group|Image|Button|Playlist|Slider|RadialSlider|Text|Checkbox|
+ Anchor|Video|Playtree|Panel)+>
+ <!ATTLIST Panel
+ x CDATA "0"
+ y CDATA "0"
+ lefttop CDATA "lefttop"
+ rightbottom CDATA "lefttop"
+ xkeepratio CDATA "false"
+ ykeepratio CDATA "false"
+ width CDATA #REQUIRED
+ height CDATA #REQUIRED
+ >