The nglview visualizer cannot be shown in the JupyterLab

I try to use the widgets with the JupyterLab from the AiiDAlab docker. However, it seems some problem with
the nglview visualizers. It shows nothing for the structures. For example, the visualizer is not working in the code
below:

```python
widget = StructureManagerWidget(
importers=[
StructureUploadWidget(title="From computer"),
CodQueryWidget(title="COD"),
StructureBrowserWidget(title="AiiDA database"),
SmilesWidget(title="SMILES"), # requires OpenBabel!
StructureExamplesWidget(
title="From Examples",
examples=[
("Silicon oxide", "miscellaneous/structures/SiO2.xyz")
]),
],
editors = [
BasicStructureEditor(title="Basic Editor"),
],
)
```

However, I test nglview visualizer inside the JupyterLab separately. The visualizer works fine.