Yeah I use the elliptical marquee tool, just position the cursor in line with the top left corner of the border, move it up about the half the height of the userbar, then drag it to the right border. With your selection, press Shift + F5 and select white fill. If you don't like your glare shape, Ctrl + T and grab the bottom central anchor point and dragit up til you're happy. Then just reduce the opacity until it looks realistic