Setting an absolute position on the THEAD works (except, I think, in old IE), but only with fixed column widths. The usual hack involves using JavaScript to keep the columns in sync.
The header cells end up being layouted separately from the body cells, and so their widths are not constrained together.
Actually, I'm not sure if sticky positioning is different in this regard... This property might not solve the problem we ran into.
In any case, a sticky header is different from an absolute header, because it doesn't require a separate scrolling container. You just scroll the page, and the header follows along, until the table scrolls out of the viewport.
The header cells end up being layouted separately from the body cells, and so their widths are not constrained together.
Actually, I'm not sure if sticky positioning is different in this regard... This property might not solve the problem we ran into.
In any case, a sticky header is different from an absolute header, because it doesn't require a separate scrolling container. You just scroll the page, and the header follows along, until the table scrolls out of the viewport.