Hi
I've noticed that the HTML CKEditor (nightly 4310) produces when you backspace into a previous paragraph is browser-dependent.
IE7 / IE8 / Opera do one thing; Firefox does another ; and Chroma / Safari yet another.
Here is a snippet of the HTML (before backspace), as shown by the CKEditor source button:
<p class="Heading1 Normal ">Formatting</p> <p class="Normal ">Now, some run formatting.