If you go to the Scala editor's Formatting configuration, it will let you set the shift width to two characters, just like everybody uses when writing Scala. This is a good thing.

Unfortunately, the behavior of the editor is not consistent with this.

In the worksheet editor, it half works. When you shift right, it shifts by two characters. When you shift left, it shifts by four characters. (If a line is indented by less than four characters, it will refuse to shift it.)

Unfortunately, the regular Scala editor is even worse. It does the correct shift only when you press return at the end of a line. In every other situation, it just picks up the shift width from the Java settings. Fixing this one little thing would make Scala far more pleasant to work with inside Eclipse.