The Workbench can be configured for the Amateras HTML plugin in a variety of ways.
You can open the Amateras preferences from the menu bar. Choose Window > Preferences and open the Amateras section. You should see a dialog such as the following.
Here you can adjust a number of different settings.
You might want to adjust the file associations, for example, making the Amateras XML editor the default for XML files. You can this by opening the file associations preferences from the menu bar. Choose Window > Preferences, open the General > Editors section, and select File Associations. You should see a dialog such as the following.
Here you change the file associations, for example making the Amateras XML editor the default for XML files.