Blogspot - add page element page element not showing properly

 when I open my Dashboard, Layout, Page Elements page there is no proper layout,

all the page element add gadget  elements are in one column,

they used to be  3 column   right hand ,middle and left hand , now they are all in one line.

Do you know the solution ?

I have cleared cache,

2nd i have uploaded my back up copy,

tried all browsers but still  problem is there.

So now if i want to add new gadget element it has become too difficult.

any solutions to solve this problem.