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.