Patch for fieldset views empty handler error

diff --git a/views_fieldsets.module b/views_fieldsets.module
index af518a6..8cfe495 100644
--- a/views_fieldsets.module
+++ b/views_fieldsets.module
@@ -65,6 +65,8 @@ function views_fieldsets_preprocess_views_view_fields(&$vars) {
*/
function views_fieldsets_views_ui_display_tab_alter(&$build, ViewUI $ui_view, $display_id) {
$view = $ui_view->getExecutable();
+ // Re-init handlers.
+ $view->inited = FALSE;
$view->build($display_id);
$ui_view->set('executable', $view);
if (Fieldset::isFieldsetView($view)) {
@@ -156,6 +158,7 @@ function views_fieldsets_form_views_ui_rearrange_form_alter(&$form, &$form_state
'relationship' => 'sibling',
'group' => 'weight',
];
+
$form['actions']['submit']['#submit'][] = 'views_fieldsets_views_ui_rearrange_form_submit';
}

@@ -167,6 +170,8 @@ function views_fieldsets_views_ui_rearrange_form_submit($form, $form_state) {
$display_id = $form_state->get('display_id');
$view = $ui_view->getExecutable();
$view->setDisplay($display_id);
+ // Re-init handlers.
+ $view->inited = FALSE;
$view->build($display_id);
$fieldsets = Fieldset::getAllFieldsets($view);
// Sort 1-dimensionally (wrong overall, but right per level).