Description
The sheet header font-weight calculation is different, depending wether the columns attribute is used.
If the columns attribute is NOT used, the browse style sheet set "font-weight: bold" on "TH".
If the columns attribute IS used, Tobago set "font-weight: normal" on "TH" and then set "font-weight: bold" on "tobago-out".
The font-weight style set for sheets with columns attribute should be removed.