There is a navigation bar, fixed.
It has a div with the ovelflow property in which child blocks are located and you need to drag blocks across the page from it using Jquery, but they disappear when dragging - they are not visible.
If you add draggable({ revert: true, helper: "clone" }); then everything works, only the original remains in its place. How to make the original disappear when you move it, and when the helper returns to its place it appears again?