Created attachment 91173 [details] demonstration of the issue As of one of the past two nightly builds, combining two paragraphs using backspace seems to insert the following markup at the end of the first paragraph: <span class="Apple-style-span" style="font-family: Times; font-size: medium;"></span> Once this takes place, the text formatting of the following content, which is rendered as if it were combined in the first paragraph, but which the HTML view shows as a separate paragraph, reflects those settings. Also, once this has happened, pressing return at the end of the combined paragraph fails to move the cursor to a new paragraph, instead opening up a new paragraph after the current paragraph and leaving the cursor in the current paragraph. I have attached a screen recording demonstrating this behavior.
<rdar://problem/9342024>
I'm told that this has been fixed in r85090. Please verify that the problem no longer occurs when the next nightly build is posted.
The nightly that was just posted resolves this issue. Thank you very much!