On 18 Jul 2009, at 12:09, Martin Kühl wrote:

...

[…] Any idea what is going wrong here?

Are you using the commands while your cursor is on the first line?

Setext-style headers are of the form

This is a heading

and the commands calculate the amount of symbols to write from the length of the actual heading. So to use the commands, write your heading, move to the next line and invoke the command.

The error message could, of course, use improvement :-)

Yeah, I’ll update it.

Just to add though: The intended use of the commands is to press return after your heading, then type either a ‘-’ or ‘=’ (depending on style of desired heading) and follow that with a press of the tab key — they are not designed to be invoked via the menu / ⌃⌘T (not that there are anything wrong with that, just a lot more tedious, and why we didn’t consider them being invoked with caret on first line of document).