Above, this page includes an iFrame. The css defines it to have padding. Pink background color fills the padding. Opera doesn't render this padding, nor the red border, on the right and the bottom of the iFrame. It appears the iFrame overflows its own container, by the combined widths of its padding and border. In the overflowed area, parts of other applications or other web pages may show.
Sometimes, you need to switch web page tabs to activate the problem. Once it shows, reloading will not make it go away.
Sometimes, you need to refresh the window to see the rendering problem.
When I omit the iFrame padding, the iFrame still overflows, by the width of its border.
