The selection dialog does not work with VSCode

[gcoutable]

Steps to reproduce

Outside VSCode:

1. Creates a papaya studio
2. In any package creates a class diagram
3. Clicks on the diagram background then on the Import existing types tool
4. Verifies the selection dialog displays a Tree

In VSCode:

1. Connects to your server, then project
2. Open the Papaya class diagram
3. Invoke the Import existing types

Expected behavior

The dialog to choose any existing type should be displayed.
It should be the exact same dialog than in the web browser.

Actual behavior

The dialog is not displayed.