Max, thank you for your reply.
Unfortunately, the hidden config does not do what is described.
The idea is by default the sort by date of adding the product to always be a DESC (first to see the latest products). All other types of sorting should be an ASC. For example, sorting by name should be an ASC.
But not only that is what is important in this hack:
Fixed display of +/-Example:https://demo.virtuemart.net/product-attributes/by,product_name?keyword=Shows product sorting +/-. This means DESC. From letter "z" to letter "a". But real sorting is ASC (-/+).
Remember the sort selected by the user when switching to another category (for the session). Including the arrangement (ascending or descending).
That means:If the user chooses sorting different than the default when he goes to another category, the selected sort is the same as he chooses. It is not the default. This only applies to the session. Like the number of products per page are remembered if the user changes them.