Background-size in Opera. Bug or my mistake?

Question

Opera

Good afternoon! Faced such a problem, which is observed only in the opera.

The bottom line is that if you set the following background parameters for the block

.operaBug {
    width: 50%;
    height: 50%;
    background-color: #555;
    background-image: url(http://habrastorage.org/storage2/87d/364/fbe/87d364fbe3ec9a89ca06dce2715071cc.png);
    background-repeat: no-repeat;
    background-position: top right;
    background-size: auto 100%;
}​

then when changing the height of the browser window, the background image can go beyond the block by 1% horizontally.

It's easier to show than to describe. Open in opera and slowly change the height of the browser window. You will see for yourself how the picture will periodically hide.

Example: http://jsfiddle.net/XAKEPEHOK/rNEE9/16/

I have Opera 12.02 Build 1578 (currently the newest). Other browsers don't have this behavior.

Answer 1

Opera bug related to a rounding error, or something like that , I think.
This can't be your fault, since in other browsers the behavior unrestrictedly achieves what you want.