When I add path to the css in some scene.getStylesheets() observable list and then show popup which is child window, all css are taken correctly, but when I change stylesheet registered to previously mentioned scene, no refresh is made to the popup until popup is reshown. A code:

popup.hide();
popup.show();

is sufficient to take effect, but css should propagate live to all child windows, not only to child components in same window and other windows after they are reshown.