Hi Yuri,
Here is the javascript console output when i run the e-learning demo you linked:
v3d.js:1 Verge3D 2.2.0
2v3d.js:1 v3d.WebGLProgram: gl.getProgramInfoLog() WARNING: Output of vertex shader ‘vNormal’ not read by fragment shader
WARNING: Output of vertex shader ‘webgl_4008bac2cdf4496d’ not read by fragment shader
Pa @ v3d.js:1
Hope this helps! Also, thank you for providing this amazing software. I hope that I find a use for it in my work.