I observed this issue on my 13-inch Mac Book Pro (OSX 10.8) with Safari version 6.0 (8536.25), so it has nothing to do with retina display. This happens when you apply the border radius to only one, two or three corners. The solution is to apply the border radius to all four corners.
This code displays a wandering vertical line:
<!DOCTYPE html> <html> <head> <style type="text/css"> body {background-color:red} #myBox { width: 960px; height: 300px; background-color: white; border-top-left-radius: 20px; border-bottom-left-radius: 20px; border-bottom-right-radius: 20px; margin: auto; } </style> </head> <body> <div id="myBox"> </div> </body> </html>
George campbell
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