public void setBackgroundColorFadeTo(String colorName) throws Exception {
		if (colorName == null) {
			lock();
			bgColorFadeTo = null;
			bgColorFadeToName = null;
			unlock();
		}
		else {
			Color color = selectColor(colorName);
			if (color == null)
				throw new Exception("Color " + colorName + " is not known.");
			lock();
			bgColorFadeTo = color;
			bgColorFadeToName = colorName;
			unlock();
		}
	}