function isCaretContainerBlock(node) {
		if (isText(node)) {
			node = node.parentNode;
		}

		return isElement(node) && node.hasAttribute('data-mce-caret');
	}
This module handles caret containers. A caret container is a node that
holds the caret for positional purposes.

@private
@class tinymce.caret.CaretContainer