Since a few weeks, when I print a document, at the Print windows (general tab) is the “number of copies”. But, it is in a closed openable “tree”, where can I see “more”. Every time, when I print, I have to open the “more” tree, to reach the “number of copies”, but it is very uncomfortable, every time to open this. Can I “freeze” in open position, or something? I don’t undertand, this feature 
Hello,
AFAIK - no you can’t set to be permanently expanded. The reason for the feature simply was a redesign of the print dialog, because there were plenty of users of LibreOffice having a display of a vertical resolution equal or less than 768 pixels and the old dialog simply has been too large for 'em. These users have not been able to click the OK button.
See bug [#tdf127782]( https://bugs.documentfoundation.org/show_bug.cgi?id=127782) - *New Print dialog is too high*
Your concern seems to be addressed by #tdf134640 - UI: Printer settings hidden under more
Maybe, if the resolution is above than 768, then the ftrre can be opened, just a simple 
May be - but people answering here are neither developers nor UI designers of LibreOffice, but users like you and hence the wrong addressees for your comment.