Image captions and block level elements

[trepmal]

After accidentally putting a captioned image inside another image's caption (yo dawg), I found that block level elements in general seem to not play well.

[caption id="attachment_809" width="150" align="alignnone"]<a href="#"><img width="150" height="150" src="http://colorto.me/png/150/rand" class="size-thumbnail wp-image-809" /></a> tree<p>block level in caption</p>[/caption] 

With <p> tag: Toggling about 3 times completely removes the tag, contents remain

[caption id="attachment_809" width="150" align="alignnone"]<a href="#"><img width="150" height="150" src="http://colorto.me/png/150/rand" class="size-thumbnail wp-image-809" /></a> tree<div>block level in caption</div>[/caption] 

With <div> tag: Toggling about 2 times causes the entire caption to be removed, after first adding some unbalanced <dd> and <dl> after the first toggle

[caption id="attachment_809" width="150" align="alignnone"]<a href="#"><img width="150" height="150" src="http://colorto.me/png/150/rand" class="size-thumbnail wp-image-809" /></a> tree<ul><li>block level in caption</li></ul>[/caption] 

With <ul><li> tags: First toggle will 'organize' your list tags, each toggle after that adds 2 <br /> tags and wraps an extra <ul> around the list.

If block levels tags aren't supported in captions, can it break consistently? Or with valid html?