Created attachment 129823 [details] test case When using the xlsx format internally in LibreOffice, cell thickness is not kept. Steps to reproduce: Create several cell borders in Cealc, and indicate which thickness you chose. Save the document as xlsx and check the cell thickness (will still be ok). Now quit the document and reopen. You will notice the cell thickness has changed: 0.75 stays 0.75 1.00 changed to 0.75 1.25 changed to 0.75 1.50 changed to 0.75 1.75 stays 1.75 2.00 changed to 1.75 There should be a way for LibreOffice to keep the thickness when using the xlsx format internally. I added my test sheet as an example how to reproduce.
It is limitation of xls/xlsx format. We cannot do much to fix that.
*** This bug has been marked as a duplicate of bug 61148 ***