<xsd:element minOccurs="0" name="skip_taskbar" type="ob:bool"/>
<xsd:element minOccurs="0" name="fullscreen" type="ob:bool"/>
<xsd:element minOccurs="0" name="maximized" type="ob:maximization"/>
+ <xsd:element minOccurs="0" name="opacity" type="xsd:unsignedByte"/>
</xsd:all>
<!-- at least one of these must be present -->
<xsd:attribute name="role" type="xsd:string"/>