In .Cells 18.104.22.168, I have some graphs and a pivot table in an XLS file which I open as the prototype (template, see attached PivotTemplate.XLS). I then add additional sheets and save the resulting file. When I save in XLS it works fine (see Marketing_Programs_Effectiveness.xls) but when I save the identical in-memory representation as XLSX it creates a bad file. If I allow Excel to repair the file the pivot table is missing (see Marketing_Programs_Effectiveness.xlsx).
Also, notice that on the "Graphs" worksheet the font sizes are different between the XLS and XLSX saved files. We would expect them to be the same as the source XLS file rather than larger as in the XLSX. Can this be fixed in the XLSX?