Custom sort with UDF as Comparer
When using the standard Sort dialog, it would be extremely useful for the 'Sort on' column to accept custom UDFs to implement the comparison of the values in the selected column.
So the 'Sort on' values would be:
* Cell Color
* Font Color
* Cell Icon
Clicking 'UDF...' will bring up a dialog displaying all UDFs implementing the IComparer interface. The user can select which one they want to use.
This will enable many scenarios such as sorting by IP addresses, MAC address etc. where standard alpha-numeric sorts don't work - they give incorrect sort orders.