This sample constructs an HTMLInfo that acts as a re-implementation of the default text editor.

The implementation is contained in the file TextEditor.ts and exposes `window.TextEditor`, which is used in this file as the value of `myDiagram.toolManager.textEditingTool.defaultTextEditor`.

This also adds a text validation predicate, `okName`, as the TextBlock.textValidation property. That predicate makes sure that the new string has at least three characters and contains a vowel.

You can see additional custom text editors in the Custom TextEditingTool sample.