This should be the normal behavior. Please show your code or, better, create and upload a little demo which shows this behavior (only pas, lfm, lpi and lpr files, packed into a shared zip).
The TsStreamParams were introduced for clipboard interaction (and, maybe, will be removed when I work with fpspreadsheet again because they are no longer needed).
Do not call Workbook.RemoveAllWorksheets, it has lots of side-effects on visual controls. Only the recent trunk version works to some degree with it.