first of all thank you for this program.
I have a pdf that is copy and paste and print protected. These features work if I open the pdf in adobe reader or a browser. But sumatrapdf tells me that the pdf is protected but I can copy and paste or print !!!
Most non Adobe readers tend to respect protection thus SumatraPDF requires the password on opening the file and will not save the file without it. However modify, printing and copy settings are “optional” and most readers such as used on Linux or Mac allow you to over-ride reader settings so as to allow for highlighting or other annotation addition , you can use older SumatraPDF or Adobe without a password if you dont want to annotate, or change the content.
No need to worry about the protection it will be preserved as it was, when the file is closed. If you dont want the file changed with highlights simply discard changes.