Since I am using C#, the in-built script editor is no good. I have set "Mono -> Editor -> External Editor" to Visual Studio Code. The problem is that now whenever I double-click a "tscn" file in the FileSystem panel, if the "tscn" file has a script, or click the "Open in Editor" button next to a sub-scene, Visual Studio Code gets launched and steals focus from the Godot Editor.
Is this a bug? If not, is there any way to stop this behaviour? I do not always want to edit the script when I open a scene.