getContext() giving ”cannot be cast to com.jme3.system.JmeCanvasContext”

Why is this code:

[java] public void simpleInitApp() {

JmeCanvasContext ctx = (JmeCanvasContext) getContext();[/java]



Giving me this exception:

java.lang.ClassCastException: com.jme3.system.lwjgl.LwjglDisplay cannot be cast to com.jme3.system.JmeCanvasContext
at niftyGui.TestXML.simpleInitApp(TestXML.java:67)
at com.jme3.app.SimpleApplication.initialize(SimpleApplication.java:225)
at com.jme3.system.lwjgl.LwjglAbstractDisplay.initInThread(LwjglAbstractDisplay.java:130)


I have even used this before with no problems.
Anyone understands what's going on?