Add helper class and style the helper

src/components/layers/LayerList.jsx

@@ -204,6 +204,7 @@ export default class LayerList extends React.Component {
   render() {
     return <LayerListContainerSortable
       {...this.props}
+      helperClass='sortableHelper'
       onSortEnd={this.props.onMoveLayer.bind(this)}
       useDragHandle={true}
     />

src/styles/_layer.scss

@@ -234,3 +234,10 @@
     min-width: 28px;
   }
 }
+
+// Clone of the element which is sorted
+.sortableHelper {
+  font-family: $font-family;
+  z-index: 9999;
+  border: none;
+}