In backend, the graphic suddenly changed

[songlei]

I got a prolbem today, my backend was normal like two column one is menu another is like article or structure. But now the left(menu) side is on top and right(article or structure) is down of the menu. I am not able to put a picture on here. So has anybody got this problem before?

[acenes]

Maybe you need to reset the zoom of your browser.