NUll Or Empty option in ComboFilter


How to add an NULL or Empty option to the combobox filter?

For example: in a row a column of name type would be

  1. Test
  2. Test 1
  3. Test 2
  4. Test
  5. Test

The combobox filter will have only “Test”, “Test 1”, “Test 2” values. Hence if “Test” option is checked, it will list all the rows of type “Test”. That is row 1,6 and 7

I would want an option “Empty” or “Null” in the combobox filter “Test”, “Test 1”, “Test 2” with , which when checked, would list row 3 and 5.

There is no way