The property can also be set by the Dim method.
This property is also functional in Web panels.
Caution: The table structure changes on setting the number of columns, i.e. the content of all cells is cleared.
The set count must be higher than FixedCols.
var oTable = pMe.Items("/Table");
var nCols = oTable.Cols; //reading
oTable.Cols = 8; //writing