Clearly the fourms are filled with issues about wordpress adding p and br tags. But this one is different.
I have build a short code plugin called collapse-o-matic. As of WordPress 3.3, upon the first use of the short code, WordPress will nearly ALWAYS insert a closing p tag. But here is the thing: the closing p tag does NOT show up when viewing source.
Want to see an example? Here, check out this demo page:
http://spacedonkey.de/
See the space between the first expand element and the rest? Well if you inspect this element you will see that WordPress had decided to insert a closing p tag between the first span and div elements that the short code creates like so:
<span class="collapseomatic" id="id3178" title="push my button baby">push my button baby</span></p><div id="target-id3178" class="collapseomatic_content " style="display: none; ">bamp chica baw-wa</div>
However, if you view the page's source: view-source:http://spacedonkey.de/ look around lines 98 and 99... there is no closing p tag to be found.
What in the world is'a goin' on a'round heyah?!