Exception in thread "main" java.lang.RuntimeException: java.lang.RuntimeException: missing childLayout attribute for an element with [1] child elements. Attributes of error element [height => 25%, backgroundColor => #f60f, valign => center, width => 35%, visibleToMouse => true, align => center, id => panel]
    at de.lessvoid.nifty.Nifty.loadFromFile(Nifty.java:534)
    at de.lessvoid.nifty.Nifty.fromXml(Nifty.java:412)
    at de.lessvoid.nifty.examples.helloworld.HelloWorldExampleMain.main(HelloWorldExampleMain.java:45)
Caused by: java.lang.RuntimeException: missing childLayout attribute for an element with [1] child elements. Attributes of error element [height => 25%, backgroundColor => #f60f, valign => center, width => 35%, visibleToMouse => true, align => center, id => panel]
    at de.lessvoid.nifty.loaderv2.types.ElementType.enforceChildLayout(ElementType.java:187)
    at de.lessvoid.nifty.loaderv2.types.ElementType.applyStandard(ElementType.java:176)
    at de.lessvoid.nifty.loaderv2.types.ElementType.create(ElementType.java:144)
    at de.lessvoid.nifty.loaderv2.types.ElementType.applyChildren(ElementType.java:251)
    at de.lessvoid.nifty.loaderv2.types.ElementType.applyStandard(ElementType.java:175)
    at de.lessvoid.nifty.loaderv2.types.ElementType.create(ElementType.java:144)
    at de.lessvoid.nifty.loaderv2.types.ScreenType.create(ScreenType.java:81)
    at de.lessvoid.nifty.loaderv2.types.NiftyType.create(NiftyType.java:137)
    at de.lessvoid.nifty.Nifty.loadFromFile(Nifty.java:527)
    ... 2 more