What were you doing:
Using CMD-3 to format a header that consisted of a line that ended with a space, eg 'The Beginning ’
What feature did you use:
‘###’ would be added to the end of the line regardless of the insertion point or what was selected
What did you expect to happen:
‘###’ to be inserted at the insertion point or at the beginning of the selection
This is a confusing bug because it often isn’t obvious that a line ends with a space before the newline character.