loadingScreen is on div conflict state when debugLayer is called at launch

[Vinc3r]

See https://codesandbox.io/s/convert-scene-add-interactions-02-grry0 (BJS v3)

CStfan give us also an example on BJS v4: http://3dmad.online.fr/WebGL/Steelcase_v0.9_custom_off/index.html , but note this is weird: on my Chrome it works, not on Firefox

[cstfan]

Under Chrome it can work on the first loading of the scene, but if we reload the scene it's blocked.