This term has been significantly change in this reauthoirzation.  Previously an tangential or attenuated relationship between the discipline infraction and the child's disability was sufficient to determine that the infraction was a "manifestation" of the child's disability.  In the new IDEA, the bipartisan consensus acknowledged that " it is the intention fo the Conferees that the conduct in question was caused by, or has a direct and substantial relationship to, the child's disability, and is not an attenuated association, such as low self-esteem, the the child's disability."  Accordingly, it is now clear in the new IDEA that the disciplinary infraction must be caused by or be the direct result of a hcild's disability, and not a mere correlation or attenuation.  Source: IDEA Guide to Frequently  Asked Questions.