Displaying the widget as red indicates that there is an error.
eheh, nice idea. I did not understand why in modifying the borderColor block the color of the shape became red.
I do not know how we can improve this, because the problem here is that red is a color used in visualization. Is it "easy" to draw a cross in shape with errors ?
Easy, but this means that some extra check will have to be done each time a rectangle is displayed (e.g., if there is an error or not when computing the metrics). These days people have been complaining about speed. I added an entry in google instead.
http://code.google.com/p/moose-technology/issues/detail?id=418
Cheers, Alexandre