Boring and pedantic point, and not occupying a high priority, but if you look at Scala's official style guide (can't link here but easily googleable!):
Indentation should follow the “2-space convention”. … [some code examples follow]
The Scala language encourages a startling amount of nested scopes and logical blocks (function values and such). Do yourself a favor and don’t penalize yourself syntactically for opening up a new block. Coming from Java, this style does take a bit of getting used to, but it is well worth the effort.
The Script Editor currently seems to apply the 4-space convention: admittedly this is what I'm used to myself and therefore seems perfectly normal to me (e.g. it's in the PEP8 Python style guide and is standard in Java) but there would seem to be some logic in following Scala's style guide. A foolish consistency is the hobgoblin of little minds etc, but Kojo's default layout, with the Script Editor and Output Pane sharing the bottom of the screen, does leave the typing space fairly narrow.