Fix: On mobile infinite scrolling didn't work anymore

- listBody.js:755 doesn't trigger an event when scrolling

client/components/lists/list.styl

@@ -180,6 +180,7 @@
     border-bottom: 1px solid darken(white, 20%)
 
   .list
+    display: contents
     flex-basis: auto
     width: 100%
     border-left: 0px

client/components/swimlanes/swimlanes.js

@@ -57,7 +57,7 @@ function initSortable(boardComponent, $listsDom) {
     tolerance: 'pointer',
     helper: 'clone',
     items: '.js-list:not(.js-list-composer)',
-    placeholder: 'list placeholder',
+    placeholder: 'js-list placeholder',
     distance: 7,
     start(evt, ui) {
       ui.placeholder.height(ui.helper.height());