protected void removeStopControl(MultiGradientFill.Stop activeStop) {
Control colorPopup = colorControlMap.get(activeStop);
controls.remove(colorPopup);
colorControlMap.remove(activeStop);
Container popupLayer = context.getSketchCanvas().getParent().getStage().getPopupLayer();
popupLayer.remove(colorPopup);
Control alphaPopup = alphaControlMap.get(activeStop);
controls.remove(alphaPopup);
alphaControlMap.remove(activeStop);
popupLayer.remove(alphaPopup);
}