It sounds like something isn't set up correctly, but I'll have to see the site before I can figure out what's happening. Are you sure that the content isn't just changing to single-column mode? The responsive themes are designed to have the side columns float to underneath the main content when the screen is too narrow to display them side by side.
Please remember to always post a link to your site when having issues with something on the front-end; I can't even begin to diagnose the cause of a problem if I can't see what's happening and inspect the code with Firebug
Hi, thank you for replying.
the site is ilhamtohti.org/ug , its RTL language, I disaabled Responsive Layouts? but I hope it should fit the screen. U can try open it with mobile device, main page will move to right side.