Sequential <br> tags are stripped from posts on update/publish

[markel]

When using either the Visual Editor or the HTML editor, line breaks, either by entering the <br> tag or by using Shift+Return in the Visual Editor, are being stripped out when flipping from one mode to the other or when updating or publishing the post.

This leave authors with no way to reliably insert whitespace without the use of non-breaking spaces or images.

To reproduce:

1. Create a new post.
2. Populate it with some text as well as a few line breaks.
3. Publish.

[azaozz]

I think you meant sequential tags as single <br> tags work properly. I'm not sure which one is worse:

<p>some text</p>
<br>
<br>
<br>

or

<p>some text</p>
<p>&nbsp;</p>

However most new browsers would disregard improperly used <br> and not show them as white space anyways.