Locking and Unlocking XML Markup

For documents with fixed markup, such as forms in which the XML tags are not allowed to be modified (only their text content), the possibility to edit the XML tag names can be disabled/enabled with the Lock / Unlock the XML tags action available in Text editing mode from:

• The Document ⇒ Source menu.
• The Source submenu from the contextual menu.

You can set the default lock state for all opened editors using the Lock the XML tags option in the Text preferences page.