Redmine

No, no plugins. Only custom theme. Yes, I did and did it carelessly as you can see. Domain is the same as host value.

BTW, I can successfully edit my comments here, so my browser is fine. It is server side problem.

I have the same issue.

I am running environment similar to yours
Gentoo amd64, Redmine 2.2.4, Ruby 1.9.3, Rails 3.2.13, PostgreSQL 9.2.4, nginx 1.4.1, unicorn 4.3.1

It is not redmine problem. I solved this problem by fixing nginx configuration.

My nginx configuration before

server {
        server_name redmine.mydomain.com;
        root /var/lib/redmine/public;

        location ~ ^.+\.(jpg|jpeg|gif|png|ico|css|js)$ {
                expires 7d;
        }

        try_files $uri/index.html $uri.html $uri @redmine;

        location @redmine {
                proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
                proxy_set_header Host $http_host;
                proxy_redirect off;
                proxy_pass http://localhost:8068;
        }

        access_log /var/log/nginx/redmine-access_log main;
        error_log /var/log/nginx/redmine-error_log warn;
}

The solution is to pass *.js reqests to the application.

My nginx configuration after (fixed)

server {
        server_name redmine.mydomain.com;
        root /var/lib/redmine/public;

        location ~ ^.+\.(jpg|jpeg|gif|png|ico|css)$ {
                expires 7d;
        }

        location ~ ^.+\.js$ {
                try_files $uri @redmine;
        }

        try_files $uri/index.html $uri.html $uri @redmine;

        location @redmine {
                proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
                proxy_set_header Host $http_host;
                proxy_redirect off;
                proxy_pass http://localhost:8068;
        }

        access_log /var/log/nginx/redmine-access_log main;
        error_log /var/log/nginx/redmine-error_log warn;
}