Relying on autoformatting to convert a series of dashes into a border is problematic because it relies on option settings and changes behaviour if spaces are involved when the Enter key is pressed.

In an ideal workflow you would remove local formatting from your content and apply styles to consistently apply borders when required. The border setting (above) could be part of the style applied to the first paragraph in a block OR be part of the style (border below) applied to the last paragraph in a block.

Removing local paragraph formatting (which includes removing those borders not part of the style) is as simple as selecting the text and pressing Ctrl-Q

__________________
Andrew Lockton
Chrysalis Design, Melbourne Australia