Bug in XHTML 1.1

When I use <form action="..." target="something"> in XHTML 1.0 strict the validator sais that the attribute target is not allowed in <form>. 
However: if I use the same text in XHTML 1.1 it doesn't say the target-attribute is not allowed! 

When I see the list of changes from XHTML 1.0 strict to XHTML1.1 it doesn't say the target-element is re-allowed. So I think this is a bug in the validator.

Kind regards, 
Sander