The DOMSET we specify only works with the first column specified. The presence of other columns is only for the notion that the sorting can also be done with other columns.
The majic layer(domsrvr) internally maintains a list which can be used for sorting with any of the columns specified in the DOMSET definition.
If the DOMSET in_list_web is specified like "open_date DESC, id DESC, mintime=min(attached_slas.time_to_violation), .......".
Whenever a list page is opened, it always sorts by the first column only i.e., open_date DESC. The presence of id DESC , mintime e.t.c means that sorting is available on these columns as well when we explicitly click the relevant column on the user interface.
In this case, the list page should sort with both z_sort2 DESC and open_date DESC. You need to write it as a composite SORT(Plus Operator +)
z_sort2=z_sort2 DESC+open_date DESC
This will sort with both z_sort2 DESC and open_date DESC