Fixedheader column width problem

veloopity

This has been discussed years ago. I wonder if there is a solution yet, more than just a workaround.
Here is an example using fixedHeader. The columns look ok while I scroll down - once I scroll up again beyond the header row, all column widths are reset, and stay there.
https://www.investmentfonds.de/sparplanfaehige-liste-fonds-etfs.cfm

-Michael