Xojo RTF cannot deal with “negative” unicode characters (that is, entities like \u-248). This is a serious problem for those who need styled text with languages like Chinese and Korean. This is a confirmed bug <https://xojo.com/issue/28050>
Unlike some RTF problem discussed on this forum, there is no workaround. I’ve been hoping with each update that this will be fixed. Is it that difficult? It’s painful to keep receiving complaints from my users who work with Asian languages and having to tell them there’s nothing I can do about it.