The color_paragraphs method of DocumentClass attempts to iterate through all the defined paragraph_type methods for each paragraph.  If a paragraph_type method returns anything but None, the colorization has been completed by the paragraph_type method, and we move on.  However, when a paragraph_type cannot be found to colorize a paragraph, we make a copy of the paragraph, and attempt to colorize its children with the color_paragraphs function.  In this case, the DOM-style attributes attached to the original paragraph were lost.  I modified the color_paragraphs method to retain the original paragraph's DOM-style attributes when a colorizer for the paragraph was not found.