If you added horizontal separator in your template and then saved it, it might be trouble removing or deleting it. The backspace will not remove the horizontal separator (HR line). The trick is
- Insert a line before the HR line if no prior line exists
- Similarly insert a line after the HR line
- Select the first line and the second line so that it encompasses the HR line. Then delete.
This is just not intuitive and can give trouble to some users, hence documenting here.