I noticed this little oddity the other day.
You should be looking at Cafe Bianco and MD Electronics, two shops in Kingston-upon-Thames. Mouse over the shop on the right and a rectangle appears, sometimes with the magnifying glass icon and sometimes without. When the rectangle is showing WITHOUT the glass, click. Then see what happens to the shop on the left.
And… one window shuts, another opens.
You have messed my head up. I’m going to bed now.