JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://code.jquery.com/ui/1.11.4/jquery-ui.js"></script>
<h2>ui.draggable + nested ui.sortable issue</h2>

<p>Steps to reproduce:
    <ol>
        <li>Pick up the Thing (draggable)</li>
        <li>Drag it in and out of the big red box (sortable) - works as expected</li>
        <li>Now drag it in and out of the small blue box (inside the big one). You'll notive that:</li>
        <ol>
            <li>When exiting the small box, the helper is flickers for a fraction of a second.</li>
            <li>When existing the large box, the helper is misplaced and will remain so until dragging back into the large box.</li>
        </ol>
    </ol>
</p>
<div class="pickbox">
    <div class="thing">Thing</div>
</div>
<div class="dropbox large-dropbox">
    <div class="dropbox small-dropbox"></div>
</div>

CSS

.small-dropbox {
    height: 150px;
    width: 150px;
    border: 1px solid blue;
    position: fixed;
    left: 375px;
}
.large-dropbox {
    height: 300px;
    width: 300px;
    border: 1px solid red;
    position: fixed;
    left: 300px;
}
.pickbox {
    height: 200px;
    width: 200px;
    border: 1px solid black;
    position: fixed;
    left: 0;
}
.thing {
    height: 50px;
    width: 50px;
    border: 1px solid steelblue;
    background: steelblue;
    color: white;
    text-align: center;
}

JavaScript

$(".dropbox").sortable({});

$(".thing").draggable({
    connectToSortable: ".dropbox",
    helper: "clone",
    //appendTo: "body"
});