We plan to introduce a change that will prevent HTML customizations done via body-end.html, head-end.html or custom index.html from being applied when the scene is opened in the Shapespark desktop editor. The customizations will still apply in the local preview mode and when the scene is uploaded or bundled.
The reason for this change is that some API operations like, for example, changing a texture via JavaScript API to a texture loaded from a remote server, can result in a scene state that can not be correctly saved from the editor. Saving such a modified scene can corrupt it.
If you are aware of cases where having the HTML customizations applied in the editor is crucial, please let us know, so we can consider how to support them.