@pichlo : the main window is actually fine. the problem comes where we need to innput password. Since i was not able to get an OK button , i simply cancelled enter password and tried to edit account settings, but there the password field is going outof screen.

I have found out the file and place where a bit of modificaion will help, but i have not really used GTK. So, anyone with a lil bit knowledge of GTK, please try adjusting the size of menu.