Yes, tautech, thanks for your help - have done all what you advised.
I can toggle between Dir and File using the top Function button,
" When in a Folder use the File button again (above the round multi control) to get access to another set of functions in the menu.", but when a try to use File button again - nothing happens, although i have already all functions in the side menu.
A can also, with pressing a Create new folder, get a pop up window "New folder", and i also can edit the new name - but than, wen i push a Enter key, window"New folder" disappear without memorizing.
I don't know would it be wise, and safe to try reloading a firmware?
Anyway, i don't use a file system much, and when, than over a USB stick - on this way, every function work es it should be.
Regards