// Create a temporary holder of ContainerShape children
List<Shape> tempCopy = new ArrayList<Shape>();

// Add active shape to the temporary holder
for (Shape shape : ((ContainerShape) pictogramElement).getChildren()) {
		shape.setActive(true);
		tempCopy.add(shape);
}

// Clear the original children
((ContainerShape) pictogramElement).getChildren().clear();

// Add the a new separate copy of the children to the shape
for (Shape shape : tempCopy) {
	((ContainerShape) pictogramElement).getChildren().add(EcoreUtil.copy(shape));
}