Welcome to SE! You don't give a lot of detail. Are you just setting up or did it work and now it doesn't?
I've seen something like this (though the menu items were part hidden under the LH WordPress menu) when I'm hosting in a subdomain. Possibly because of the symlinks in my hosting provider. I got round this by going to Adminster >> System Setting >> ...
The difference between readonly and disabled is a common thing with HTML and forms.
See for example https://stackoverflow.com/questions/7730695/whats-the-difference-between-disabled-disabled-and-readonly-readonly-for-ht