Elem() with no namespace prefix?

[djbpitt]

I don't know whether the follow issue reflects a suboptimal detail in the scala-xml API or whether my IDE is raising a spurious warning, and I'm inquiring here in case it's the former. Here are the details:

The Elem() constructor expects a string, representing a namespace prefix, as its first argument. An empty string throws an error:

IllegalArgumentException: prefix of zero length, use null instead

Using null works, but IntelliJ raises a warning:

Using Option is a safer alternative to null

I can suppress the warning in the IDE, but should I have to? That is, is there a reason that the prefix argument is String (with an implementation that does not accept an empty string) instead of Option[String]? Or is IntelliJ being incorrectly alarmist in a situation where the use of null is, in fact, properly idiomatic in Scala 3?