In this video you can see a demonstration of a 787 electrically dimmable cabin window. You can see that the window goes from full clear view to full dimmed in 100 to 110 seconds. The reverse operation, back to full clear takes more than 3 minutes. This could make the passenger think that the dim function of the window is not working, and subsequently the passenger pushes the control button over and over again. This in time will damage the button way before the time it was designed for.