Markdown demo broken (ul, h#, ...) puts html into Markdown field (chromium)

Example : On http://hallojs.org/demo/markdown/, selecting the second paragraph, clicking the ul button gives in source div :

*   <span style="font-size: 16pt; line-height: 21pt; text-indent: 2em;">Actually, this text [snip] some text.</span>

Then, clicking h1 button three (3) times gives :

# <h1><h1>

*   <span style="font-size: 16pt; line-height: 21pt; text-indent: 2em;">Actually, this text [snip] some text.</span>
</h1></h1>

It looks like it's actually a to-markdown issue. Removing font-size, line-height and text-indent from hallo.css article p solves this issue.

Affected browsers :

Not affected :

bergie / hallo