New line characters after the start tag of a section, or after a comment, are discarded. I may be wrong but I think they shouldn't be.

Here is the example from the doc with a little modification (the ~ at the of the {{#each}} expression was removed):

{{#each nav}}
  <a href="{{url}}">
    {{~#if test}}
      {{~title}}
    {{~^~}}
      Empty
    {{~/if~}}
  </a>
{{~/each}}

with:

{
  nav: [
    {url: 'foo', test: true, title: 'bar'},
    {url: 'bar'}
  ]
}

results in:

  <a href="foo">bar</a>  <a href="bar">Empty</a>

Instead of:

  <a href="foo">bar</a>  
  <a href="bar">Empty</a>

Edit: When rereading the documentation, I see that:

This expands the default behavior of stripping lines that are "standalone" helpers (only a block helper, comment, or partial and whitespace).".

So I guess this post is most likely an enhancement request: would it be possible to disable this default behavior?