> Does the attached patch fix the problem? It sets mhchem to 0 if the > original document is from version 1.5.x or older.
Great! That indeed fixes the problem for me! Thanks a lot! Probably one should do the same for all packages whose support was added at a later stage and for all future new supports: Set their default "off" for all older lyx-documents... For me personally it's now fine. But I think that it's quite a serious issue because of the possible data loss. And I could imagine that the same things happen for old documents that redefined in a similar manner ams-functions (imagine somebody having defined "\tfrac" to be some macro without argument instead of a macro with two arguments as it is supported). What I still don't understand: even if the support is wrongly loaded, it should not change the content of the document, but only the way it's being displayed and then being reversible by onloading the package-support, shouldn't it? Is there no way to make such data-losses impossible, even if some package is loaded by mistake? Best regards, Sebastian
