execCommand('insertHTML', ...) creates nested paragraphs under very specific circumstances

• Component: HTML Editing
• Status: NEW ---

[Tim Molendijk]

Steps to reproduce the problem:
1. Open provided URL
2. Click button to execute code as described on its label
3. Notice how a nested paragraph structure has been created (and the first inserted paragraphs ends up last in the created DOM tree - but that's probably related)

What is the expected behavior?
What Firefox does: create a DOM tree that looks like this:
<p>1st inserted</p>
<p><br></p>
<p><br></p>

What went wrong?
Instead it creates a DOM tree that looks like this:
<p><p></p></p>
<p>1st inserted</p>

Does it occur on multiple sites: Yes

Is it a problem with a plugin? No 

Did this work before? N/A 

Does this work in other browsers? No Safari (verified v7.0.1)

Chrome version: 34.0.1797.2  Channel: dev
OS Version: OS X 10.9.1
Flash Version: Shockwave Flash 12.0 r0

As soon as a layout is applied to all paragraphs, this misbehavior disappears. Or when the br element is removed from the initial contenteditable, this misbehavior disappears. And probably several more subtle requirements that I haven't discovered.

[Tim Molendijk]

I'm not sure whether "layout is applied" in the last paragraph is correct. I _am_ sure that when you apply min-height to every p (in CSS), the problem goes away.