#2 xml:lang is not displayed in the HLE if it already exists

[Charles Schmidt]

The xml:lang field is gathered from XML and so will not appear as a field of an element in a High-Level Editor. It can still be added and adding one correctly replaces the existing xml:lang in the XML. However, once the file is closed and opened again, the same element's HLE would not show the field until it was re-added manually.