In order to reproduce the issue, you need to call Window>Preferences
You will get the following messages:
Invalid preference page path: JSP Occurrences
Invalid preference page path: XML Occurrences
The issue is caused by changes in wtp's preference pages.

There is also a problem of initializing preferences within XML Occurrences (it also exists in the 2.1.x version).
The issue can be reproduced by opening this page in a new workspace before opening some xml editor.
All the preferences will be "false". This happening because the org.jboss.tools.common.text.xml plugin changes the preferences of the org.eclipse.wst.xml.ui plugin what causes the initializer of the org.jboss.tools.common.text.xml plugin no to be called.
The initialization of these preferences is called in the XMLTextEditor constructor.
In my opinion, it would be better to call it in the XmlEditorPlugin constructor. In that case, they would be initialized correctly before opening some xml editor.