This is what it looks like. Exactly as it appears on my screen. The issue shows up in both Processing 1.2.1 and 1.5.1 so I suspect that it's something my Windows 7 setup is somehow causing. Note that the blur in the Standard Examples window also appears in the command line output at the bottom of the main window, and is spread every frame. Meaning that every time that frame is updated it gets blurred by what looks like 1 pixel. What you see in the Standard Examples window was created by scrolling to the bottom and then back to the top, causing the bottom to be blurred more because it's been updated more often.

When I start Processing, often the whole screen is black, and as parts of the interface are forced to update, their areas are revealed. You can see what that looks like in the screenshot, where I navigated to the second sketch in my sketchbook.

I have never seen anything quite like this, indeed the blur that this bug produces looks really nice and I have no idea where it might be coming from. Any ideas?