allow hidden item in axis

Many customers asked to set sort order on an axis by defined orders.

For example for string column, a custom sort order can be specified on it and changes sort order arbitrarily, however if there are too many unique values custom sort oder can not be used.

Other case like (1) sort numeric value in Y axis of cross table descendantly, (2) sort column dynamically by other columns' value, (3) sort column by another column which contains numbers that defines sort order , etc.

For some cases above we can use a calculated column like rank([col], "desc") as first item on the axis to sort other columns followed, howerver the rank([col], "desc") column is shown on axis which is actually not expected to be seen.

So this idea would be hide some items(the colums used to set sort order in this case) set on an axis.

i.e.if expression "< [sort order] NEST [position]>" is set on X axis of an bar chart, customer wants to hide [sort order] from the X axis and only show [position] on it.

Thanks.