If it is in the bootom of the section, drag the height of the section down,
and you will be able to remove it.

If it is at the top of the section, drag the mouse upwards through the line.
That will select it, and you can remove it.

If there are other controls the entire width of the support, start below the
control and drag up through it. The title bar of the Properties box will
indicate multiple selection. Ctrl+Click the other selected control. You now
have the line selected.

If you are still stuck, choose the lines in turn in the drop-down list on
the toobar in report design view, or select anything in the section and
keeping tabbing to the next control until you land on the line.