A lot of time one does not want to bind an attribute to an EL expression, one only wants some help with the list of valid values for the attribute of an XHTML/HTML tag, on those cases current Content assist is very inconvenient.

Java Content Assist has several "Proposal Kinds", and one can switch between them by repeatedly using Ctrl+Space. But when editing a JSF/SEAM/XHTML/HTML/JSP this behavior is not available, all the SEAM options are shown first, and, only after them the "XHTML/HTML" options are shown.