Using function snippet leads to code duplication

Using function snippet/template leads to strange behavior with code duplication:

Steps to reproduce:

• Insert function snippet using CTRL+SHIFT+P for example
• Once the snippet is inserted, edit it using keyboard only
• Once function and parameters names are set, just move your caret down and start writing some code...

Multi-line edition should be disabled once initial snippet has been edited.

See: https://scilab.discourse.group/t/pb-with-vscode-current-extension/