[whatwg] Make <th> be a header cell for its row even for the first row

[Simon Pieters]

Many pages use tables where only the first column are header cells, e.g.:

    <table>
     <tr><th>Foo <td>Bar
     <tr><th>Foo <td>Bar
     <tr><th>Foo <td>Bar
    </table>

With the current algorithm for assigning header cells to data cells, the  
first <th> won't be a header cell for any data cells. In order to be more  
compatible with existing content, and in order to not require authors to  
use more complex markup for such a simple table like the one above, I  
think it probably should be.

I think it would be if the following paragraph was inserted between the  
first and the second paragraph in the "auto" state of the algorithm:

    Otherwise, if the header cell is both in the first row and in the first
    column of the table, and there are no other header cells in the same
    row, then assign the header cell to any data cells anchored at slots
    with coordinates (data_x, data_y) where header_x < data_x ≤ x_max and
    data_y = header_y


Regards,
-- 
Simon Pieters