Room Divider Gone Wild!

[rlackore]

In version X5 or earlier, you should never is an invisible wall or any wall type that has a zero thickness overall for the wall type.

Using a zero-width invisible wall in X5 is an attempt to accomplish exactly what the X6 room dividers are meant to accomplish; whether you "should" or "shouldn't" I won't argue - it's just another example of a work-around to make up for missing functionality.