Schema validation errors
In some cases the offical DITA 1.2 xsd's reject documents that are valid according to the official DITA 1.2 dtd's.
The official XML Schema files (xsd's) as linked in the DITA 1.2 specification are not a 100% match with the official DocType Definition files (dtd's). Since the CMS validates your documents based on dtd's and the editor validates your documents using xsd's, this means that with some topics the exceptional situation can occur that the topic is valid according to the CMS, but that the editor will show a message that the document is not valid.
Uncaught DOMException #16: Element 'lcTrueFalse' is unexpected according to the content model of parent element 'lcChallenge'. Expecting: optionally dl, note, data, title, ph, table, keyword, term, tm, state, boolean, p, lq, q, ul, ol, sl, fig, pre, lines, image, object, simpletable, draft-comment, required-cleanup, fn, indextermref, cite, xref, data-about, foreign, indexterm, unknown, lcInstructornote, imagemap, sup, sub, tt, b, u, i or sectiondiv or character data
These updated schema's are not officially approved by the DITA technical committee though. Therefore they should be used with care, other problems might appear when using these unofficial schema's.