Hi,
If B is a specialization of A, then B inherits attributes from A, but A cannot use attributes defined only in B in an xpath constraint.
So if the boolean exists only on B, you should query B, not A - or move that attribute to A if it must be used for filtering at the generalized level.
Hi Bo Sung Kim,
You can filter entity A based on a Boolean attribute in its specialization (B) by casting to the subtype in XPath:
[YourModule.B/YourBoolean = true()]
This works because B inherits from A, and XPath allows filtering A using attributes of its specialization