If you apply the CSS -webkit-transform: scale(-1,1) to an HTML <input type="button" /> it causes the button to draw correctly in the sense that it is a mirror image but incorrectly in the sense that the two ends of the button are missing. The Firefox 3.1 beta for OS X draws a backwards/reversed button without this visual error. Incidentally, I kind of think this bug didn't exist when CSS transforms were first introduced.
I also included animation of the CSS scale() property in the example . If you look very closely you can see that when at a negative scale, the button leaves little bits of itself behind as it is animated. It does not paint correctly.
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Created attachment 27639 [details]