Impossible to delete elements on a diagram from the VS Code extension

[pcdavid]

1. Open a diagram in the VS Code extension
2. Select an element
3. The palette appears. Click on the "Delete" button
4. Nothing happens.

I suspect this is due to the confirmation dialog, maybe because it relies on local storage to decide whether or not to appear, and that API is not available (or not in the same way) from inside VS Code. This is pure speculation though.