When I am working with a particular file (file1.txt) and click View > No Wrap, this mode is automatically applied to another file (file2.txt) when I switch to (or open) it, so I need to spend some time and energy to click View > Wrap by Window to work with this file. Then when I switch back to file1.txt, I need to click View > No Wrap again because this file is in the Wrap by Window mode; when I switch to file2.txt, I need to click View > Wrap by Window again, and so on, which is very annoying to me. Is it possible to prevent the wrap mode of the active (focused) file from being automatically applied to all other files?
Yes. Clear the Synchronize Wrap Mode check box in the View page of the Customize dialog box.