Flickering when using ofEasyCam on iOS device

Hello,
I am trying to use the iOS with ofEasyCam but get flickering on Device (iPad 4). Code is very simple:

CircleApp.h

	class CircleApp : public ofxiOSApp {
	public:	 	
		ofEasyCam										mCam1;
	}

CircleApp.mm

	//--------------------------------------------------------------
	void CircleApp::setup(){	    
	    ofBackground(0);
	    ofSetVerticalSync(true);
		ofEnableDepthTest();
		mCam1.setupPerspective(false, 60, 0.1, 3000);	    
		mCam1.lookAt(ofVec3f(0));
	}
	//--------------------------------------------------------------
	void CircleApp::draw(){
		mCam1.begin();
	    ofCylinderPrimitive sph;
	    sph.set(20, 30, 30, 30);	    
	 mCam1.end();       	    
	}

What am I missing?