We have added header section for parameter tab deliberately so that we can force user to select parameter name (and therefore parameter's data type) before adding new row. This is required because behavior of second cell (Value cell) is dependent on what parameter name user has selected in first cell (Name cell). See attached screen-shot.
For example: 1. If user selects parameter 'array_nulls' then value for this should be either true or false (and hence switch cell). 2. If user selects parameter 'cpu_index_tuple_cost' then value for this should be Integer (and hence Integer cell).
Without the custom header (and forcing user to select parameter) we cannot decide what type of cell we need in second column.
Let me know your opinion on this.
Apart from this I have fixed column resize issue for Security label tab. For Privileges tab I have reduced column resizing margin at some extent but not 100%.