I have a spreadsheet with a header row followed by several rows of data. I
want to add a combo box item so that users can select a sub-set of the column
headings and then run a macro to sort by this selection

e.g row 1 has A1= head1 A2=head2 A3=head3 A4=head4

I want to add a combo box to offer head1 and head4 as sort options, I am
using the forms toolbar and enter the combo box OK and can assign a sort
macro OK but when I try and use A1,A4 as the input range I get "reference is
not valid" error message. the input range only seems to work if it is in
column order not row order. As my headings already exist I wanted to use
those as the input fields into the combo box. Is this possible?

Many thanks