Howdy 
I hope that I am in the right section of the forums to report this issue.
When I reached the local user’s section of the installer, I chose the default option that makes my primary username’s password have administrative permissions. However, after the installation, the user manager’s administrator box is unchecked 
Is it normal to happen or is it a bug?
Thanks in advance!
I do not quite understand what you mean.
As far as I know, the installer offers you as default to have the same password used for root and for the user you are asked to create there. Which is btw for many seen as a bad situation that should not have been made the default.
It means that when you are asked for the root password (e.g. when starting YaST or a Terminal in “administrator mode”), you have to use the same password as you used to login with the normal user. That may be easy for your memory, but is not very secure.
I have no idea what you mean with “the user manager’s administrator box”, or where you see such a thing.
No, it doesn’t.
It just sets the root’s password to be the same as for your user account.
They are not even synced though, if you later change your user password, root’s password will stay the same.
However, after the installation, the user manager’s administrator box is unchecked
Is it normal to happen or is it a bug?
That’s normal.
There is only one “administrator”, and that is root.
Btw, that checkbox doesn’t do what you probably think it would…
And next time please also tell what “user manager” you mean here.
I suppose it’s the one in the desktop settings, but which desktop?
I am sorry if I was not detailed :shame:
I tried to show a screenshot of the problem, but the Insert image button seems to only work with URL images.
I am using KDE Plasma Desktop and the User Manager is in System Settings > Account Details > User Manager.
Point is you user does not have root privileges you stillmust become root to administer system and the dealt is to have root’s and first user’s passwords the same.
One way to post images is by uploading them to http://paste.opensuse.org/and post the links here.
You are now using openSUSE. One of the best things in openSUSE is YaST. YaST is the system management tool of openSUSE. Thus better use YaST. It has a user and group management module:
YaST > Security and Users > Users and Group Management.
So if I understood correctly, by default root’s password = primary username’s password, and if I only change my primary username’s password, the root’s password remains the same?
Also, as root, I saw the content of /etc/sudoers and my primary username is not there, so by default my primary username is not allowed to use sudo?
Yes.
root is a user like any other (although with more powers of course).
That installer option only decides how the root password is set initially. (if you deactivate it, you will be asked for a specific password for root during installation)
Also, as root, I saw the content of /etc/sudoers and my primary username is not there, so by default my primary username is not allowed to use sudo?
Everybody is allowed to use sudo on openSUSE (with the default settings).
You need to know/supply the root password though.
It’s different in Ubuntu e.g., where only certain (“administrative”) users are allowed to use sudo, and they need to supply their own password. The root account is completely disabled there.
In openSUSE OTOH, you can even login as/switch to (with “su”) being root. It’s not a good idea to run a graphical session as root though.
PS: I think the only thing that “Administrator” checkbox does in KDE’s (and also GNOME’s) user-manager is that it would allow to modify (or add/delete) other accounts (in the user-manager, otherwise you need to be root to do that anyway).
In simple terms, openSUSE is not Ubuntu. But you will soon get used to the differences.
With Ubuntu, you could make a user an administrator. Technically, that added the user to the “wheel” group. There’s also a “wheel” group in openSUSE. But it doesn’t actually do much. If the KDE user manager allows you to set a user as administrator, that probably adds it to the “wheel” group. But, as I just said, that doesn’t do much.
In Ubuntu, the “sudo” command is configured to treat the “wheel” group specially. It does not have that configuration in openSUSE, though you could probably set that up.
If you need to do something administrative, you can open “Terminal - Super User mode”. That will prompt you for the root password. When you finished doing superuser stuff, just close that terminal. Some applications are setup to ask for the root password when you open them.
Thank you all for your replies
How can I mark this thread as solved?
You are welcome.
No special action needed.