+Django 1.3, MySQL and Proxy Models
+Due to a `bug in Django 1.3`_, deleting nodes could be problematic
+**ONLY** under the following conditions:
+ * Proxy models are used. Most users don't use this. If you are not
+ sure that you are using proxy models, then you are not, and
+ shouldn't worry about this.
+Solutions to this problem, either:
+ * Don't use proxy models
+ The actual problem resides in MySQL. This Django bug
+ is a regression because Django stopped working around
+ a limitation in MySQL: MySQL, even while using InnoDB,
+ doesn't support referred constraints checks (which is
+ enough reason to upgrade to PostgreSQL).
+Due to this, ``treebeard`` doesn't support this problematic
+configuration and the test suite expect failures (xfail)
+.. _`bug in Django 1.3`: https://code.djangoproject.com/ticket/17918