[New problem] Can't see messages in folder

Starting a few days ago, very close to the recent 68.3 update, some of my folders will not show the contained mails, they only show white rows. I have had this problem in the past and it was fixed by hitting "Reset columns to default". That option doesn't exist anymore. It has been replace by "Reset column order" and using this doesnt help at all. Please help "Update:" I have realized that all the columns in the mail listing were deselected for some reason. The problem now is that i dont have a 'Subject' column. I could re-add other columns they were in the little column selection but not 'Subject'. This is happening for only for two of my folders, all the other folders are ok, are showing the 'Subject' column, but the 'Subject' column is not in the column selection list, so i cant select it or deselect it. And if i use "Group by sort parameter" all the group headers are broken and dont show anything... so the folder itself is still broken