2.1. A strictly validating XML editor

XMLmind XML Editor (XXE for short) is advertised as being a strictly validating XML editor. But what does this mean?

If the document opened in XXE is initially valid —in our case, conforms to the TEI Lite grammar— then XXE will not let you modify this document in a way which would make it invalid. For example:

You may not delete the title child element found in a titleStmt element (because a titleStmt element must start with one or more title elements).
You may not insert a division between two paragraphs (this is specified in the content models of body and div)
You may not set an xml:id attribute to a number (because an ID attribute may not start with a digit).

What about an invalid TEI document created outside XXE?

Of course, you can open an invalid TEI document in XXE[1] and still be able to edit this document. When this is the case, you'll see something like this:

Figure 2-1. An invalid document opened in XXE

The "Validity state" indicator shows a blinking red cross .
The Validity tool is brought to front and lists a number of error messages. Clicking the number of an error message selects in the document view the element where the validity error was found.
Please remember that XXE currently only supports TEI Lite and no other TEI tagset. Therefore you may open a perfectly valid TEI document in XXE and still get thousands of the most severe validity errors. This happens simply because your document uses TEI elements (e.g. the ab and egXML elements) beyond those found in TEI Lite.
For example, opening the original "tei_lite.doc.xml" —C.M. Sperberg-McQueen and Lou Burnard, TEI Lite: Encoding for Interchange: an introduction to the TEI— in XXE causes the Validity tool to list 10 359 error messages!

This blinking red cross Most severe error indicator means that the document has the most severe validity errors[2]. For example, an unknown element was found in the document.

You are expected to fix all these severe validity errors before actually using XXE to add content to your document.
If you cannot or do not want to fix all the severe validity errors, then we recommend to stop using XXE. Our XML editor has not been designed to function normally in presence of severe validity errors.

[1] You can even open a non-well-formed document in XXE but in this case, you'll see just the raw XML source of your document.

[2] The "Validity state" indicator may display several other icons. For example Least severe error indicator

, which means that the document has minor validity errors such as bad cross-references. Working on a document which has bad cross-references is very common, so you should not be alarmed by this situation.