To group table columns, table rows must be preceded by <colgroup> elements that determine the extent of each group:
[Tables]
; ColGroupElements = No (default) or Yes (to put out <colgroup>
; elements before first table row; needed to enable scope="colgroup")
ColGroupElements=No
This setting is intended primarily to support WAI interpretation using the WAI scope attribute; see §35. Identifying HTML table structure for WAI for more information. However, you can use this setting also to add CSS class attributes.
DITA2Go generates <colgroup> elements, but not <col> elements. The main use of <col> is to give a column a class attribute, so you can apply column-specific formatting (borders, shading) in CSS (see §31. Setting up CSS for HTML). To use <col> elements, specify them in [TableStartMacros] (see §33.6.1 Invoking macros around tables), and supply the needed attributes there. For example:
[TableStartMacros]
sometable=
<colgroup>
<col span="2" class="LeftSide" />
</colgroup>
<colgroup>
<col class="UnitPrice" />
<col class="MinQty" />
</colgroup>
If you provide your own <colgroup> and <col> elements this way, either set ColGroupElements=No (for all tables), or override ColGroupElements for those tables where you supply these elements; see §33.3.2.6 Overriding row and column group settings.