CSS2DRenderer with WebGLRenderer not working - three.js

Question

I started working with this example where both, a CSS2D Renderer as well as a WebGL Renderer is used - it works fine.
Now, I want to load object files and add CSS Labels to it. I started with the OBJ-Loader Example. There, the renderer is created as follows (all the following code snippets refer to the loader example):
initGL: function () {
this.renderer = new THREE.WebGLRenderer( {
canvas: this.canvas,
antialias: true,
autoClear: true
} ); .....
Thre renderer is called as follows:
render: function () {
if ( ! this.renderer.autoClear ) this.renderer.clear();
this.controls.update();
this.renderer.render( this.scene, this.camera );
}
My problem is that I do not know how to integrate the CSS2 Renderer. I simply tried to add the new labelrenderer to the same positions of the WebGLRenderer but it seems not to work:
initGL: function () {
this.renderer = new THREE.WebGLRenderer( {
canvas: this.canvas,
antialias: true,
autoClear: true
} ); //same code as before
this.labelRenderer = new THREE.CSS2DRenderer();
document.getElementById( 'example' ).appendChild(this.labelRenderer.domElement );....
I tried to update the render also at the same position of the WebGL Renderer:
render: function () {
if ( ! this.renderer.autoClear ) this.renderer.clear();
this.controls.update();
this.renderer.render( this.scene, this.camera );
//same code as before
this.labelRenderer.render(this.scene,this.camera);
}
The result: the WebGL renderer seem to work (the model is loaded) but the webgl renderer is not working... I do not get any error message but I simply do not see any label. What do I wrong? I create the label as follows:
var earthDiv = document.createElement( 'div' );
earthDiv.className = 'label';
earthDiv.textContent = 'MYLABEL IS NOT SHOWN';
earthDiv.style.marginTop = '-1em';
var earthLabel = new THREE.CSS2DObject( earthDiv );
earthLabel.position.set( 0, 3, 0 );
scope.scene.add(earthLabel );

Answer 1

I found the solution. The problem was that the CCS2 Object was added to the wrong div:
document.getElementById( 'example' ).appendChild(this.labelRenderer.domElement );
Of course, both, the canvas from the WebGL Renderer and the dom of the label Renderer have to be added to the same parent (the element example was the dom of the webgl renderer)
Thank you soo much for your support!