Hi Christos,
Nearly all label reports are defined with special headers for sorting (Group Headers QSLSortKey and QSLMGR). This is done this way because most bureaus requires QSL to be sorted by DXCC. With these headers QSL labels are sorted by DXCC and QSOs via QSL Manager, will be included in the QSL Manager's callsign DXCC. You can change the sorting method for certain countries. Please read carefully the chapter "Sorting QSL Cards" to understand how all this works:
https://swisslogforwindows.com/english/H...0Cards.htm
Summing up: You should not change this and sort by date/time, otherwise you will make things very complicated to your bureau.
If you still want to do it your way, go to the Layout tab, mouse right click then select Arrange section and delete both Group headers. You will be able to sort by any other field.
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