I often use Sigmaplot ™ to produce nice plots but it often crash when pasting raw data from libreoffice.calc. I’ve always to copy and paste cells to a plain text program (i.e. notepad) and then I can copy and paste from plain text to sigmaplot sheet. It seems there is something in the calc cells that is not digested by sigmaplot sheet, but everything “clean” itself during plain text pasting. Any idea?
LibreOffice puts the data in lot of formats into the clipboard. It would be interesting, which one Sigmaplot tries to import. Perhaps you can start a series of experiments: Do not use the clipboard directly, but save the spreadsheet to file in several formats. Then try to import such file in Sigmaplot.
Or you ask the producer of Sigmaplot about the order of tried import filters for the import of the clipboard. Or perhaps they can reproduce your problem and tell you, which format Sigmaplot has tried on import.
Without knowing, which of the formats was used and fails, it is difficult to improve the interoperability.