Created attachment 167928 [details] File for testing During saving ods file as xlsx there is some information lost about border thickness - there are no thicker borders. Steps to Reproduce: 1) Open test.ods from attachment 2) Save it as xlsx 3) Open saved xlsx in LibreOffice Visually the tables are not the same.
Excel (and its formats) do not have the concept of border width. We can't save to a format something that is not supported there. That's what the warning tells you about which is shown when you export to non-native format (unless you disable it). Closing NOTABUG.
To clarify: Excel only has border styles. They include several styles that define kind of "thickness": namely "hair", "thin", "medium", and "thick", that is prints as 0.05, 0.75, 1.75, and 2.5 pt wide respectively. Thus LibreOffice has to round the finely defined cell border width towards the nearest Excel's style. The styles that Excel uses in OOXLM are defined in ECMA-376-1:2016 sect. 18.18.3 ST_BorderStyle (Border Line Styles) [1]. [1] http://www.ecma-international.org/publications/standards/Ecma-376.htm
Oh, I see. The thickness of 1.5 is saved as 0.75 during export to xlsx, but with 1.75 everything is OK. Thank you for the clarification !!!