Listbox and "select all" option - How to adapt this code?

[Grek]

And actually to unselect everything / set value to null as if the form was just opened, what is the code?
Thanks

[June7]

Think maybe union a (None) option into the comboboxes RowSources and modify function code like:

        If lbo.ItemData(item) <> "(None)" And (If lbo.ItemData(item) = varValue Or lbo.ItemData(item) = "(All)") Then
            IsSelectedVarClients = True
            Exit Function
        End If

Then could also have a button Click event that would set both listboxes to the (None) row and null the combobox.

Might also need to requery the form: Me.Requery