BUG|Some sentences cannot be indented correctly

Testing version:

What were you doing:
indent one sentence

What feature did you use:
Click to indent

What happened:
Some sentences cannot be indented correctly.

What did you expect to happen:
indent a sentence

This is the correct behavior due to how Markdown works: adding a tab (or 4 spaces) at the beginning of a paragraph makes it code.

This is a link to the Markdown specification with some explanation.