diff --git a/doc/source/operations.rst b/doc/source/operations.rst
index 365c198..f744148 100644
--- a/doc/source/operations.rst
+++ b/doc/source/operations.rst
@@ -75,8 +75,9 @@
 Merging of parameters is done "deeply", meaning that lists and dictionaries
 are extended (recursively), rather than replaced. However, a scalar value
 *does* overwrite a dictionary or list value. While the scalar could be
-appended to an existing list, there is sane default assumption in the context
-of a dictionary, so this behaviour seems the most logical.
+appended to an existing list, there is no sane default assumption in the
+context of a dictionary, so this behaviour seems the most logical. Plus, it
+allows for a dictionary to be erased by overwriting it with the null value.
 
 After all classes (and the classes they reference) have been visited,
 |reclass| finally merges the applications list and parameters defined for the