'Unknown Source' when stepping into another file.

[buonan]

Description

I followed the steps from this article. https://medium.com/@thunderz99/debugging-kotlin-program-using-vscode-318ed43fe2f0

Extension version

I have VSCode Kotlin plugin version v0.2.22 installed.

Additional context

If you add another Kotlin file in a subfolder and call it from main() you cannot step into that function in the debugger. You get 'Unknown Source'