When you first create multi-line reports, you create multi-line headings as well. If you do not want multi-line headings, you can edit them separately from the rest of the View.
To suppress the printing of headings drag the thick black dividing line, located between the column headings and the vertical scroll bar, upwards to cover those column headings you do not want to print. You must leave a heading of at least one line (which may be blank).