Replacement patch https://gist.github.com/junaidpv/4e121aa04edcda533a8b36acf02ae915 . To allow to set short title on calender events.

fullcalendar_view-short-title-for-5.x.patch

diff --git a/js/fullcalendar_view.js b/js/fullcalendar_view.js
index 35ad731..500fbfc 100644
--- a/js/fullcalendar_view.js
+++ b/js/fullcalendar_view.js
@@ -35,7 +35,7 @@
     // Show Tooltip on Mousehover
     let thisEvent = info.event;
     let des   = thisEvent.extendedProps.des;
-    let title = thisEvent.title;
+    let title = thisEvent.extendedProps.regular_title;
     if(des.length > 0) {
       $(info.el).fullCalendarTooltip(title, des);
     }
@@ -277,6 +277,16 @@
       calendarOptions.eventDrop = eventDrop;
       // Language select element.
       var localeSelectorEl = document.getElementById('locale-selector-' + viewIndex);
+
+      let urlParams = new URLSearchParams(window.location.search);
+      let fcview = urlParams.get('fcview');
+      if (fcview) {
+        // for v4
+        calendarOptions.defaultView = fcview;
+        // for v5
+        calendarOptions.initialView = fcview;
+      }
+
       // Initial the calendar.
       if (calendarEl) {
         if (drupalSettings.calendar) {
diff --git a/src/FullcalendarViewPreprocess.php b/src/FullcalendarViewPreprocess.php
index bd0964d..43f865f 100644
--- a/src/FullcalendarViewPreprocess.php
+++ b/src/FullcalendarViewPreprocess.php
@@ -183,6 +183,18 @@ class FullcalendarViewPreprocess {
         else {
           $title = t('Invalid event title');
         }
+
+        // Event short title.
+        if (empty($options['short_title']) || $options['short_title'] == 'title') {
+          $short_title = $fields['title']->advancedRender($row);
+        }
+        elseif (!empty($fields[$options['short_title']])) {
+          $short_title = $fields[$options['short_title']]->advancedRender($row);
+        }
+        else {
+          $short_title = t('Invalid event short title');
+        }
+
         $link_url = strstr($title, 'href="');
         if ($link_url) {
           $link_url = substr($link_url, 6);
@@ -197,7 +209,8 @@ class FullcalendarViewPreprocess {
           foreach ($start_dates as $i => $start_date) {
             $idkey = $row->index . '-' . $i;
             $entry = [
-              'title' =>  Xss::filter($title, $title_allowed_tags),
+              'title' =>  Xss::filter($short_title, $title_allowed_tags),
+              'regular_title' =>  Xss::filter($title, $title_allowed_tags),
               'id' => $idkey,
               'eid' => $entity_id,
               'url' => $link_url,
diff --git a/src/Plugin/views/style/FullCalendarDisplay.php b/src/Plugin/views/style/FullCalendarDisplay.php
index 5354e1b..1428637 100644
--- a/src/Plugin/views/style/FullCalendarDisplay.php
+++ b/src/Plugin/views/style/FullCalendarDisplay.php
@@ -69,6 +69,7 @@ class FullCalendarDisplay extends StylePluginBase {
     $options['start'] = ['default' => ''];
     $options['end'] = ['default' => ''];
     $options['title'] = ['default' => ''];
+    $options['short_title'] = ['default' => ''];
     $options['duration'] = ['default' => ''];
     $options['rrule'] = ['default' => ''];
     $options['bundle_type'] = ['default' => ''];
@@ -160,6 +161,13 @@ class FullCalendarDisplay extends StylePluginBase {
       '#options' => $field_names,
       '#default_value' => (!empty($this->options['title'])) ? $this->options['title'] : '',
     ];
+    // Field name of short_title.
+    $form['short_title'] = [
+      '#title' => $this->t('Short Title Field'),
+      '#type' => 'select',
+      '#options' => $field_names,
+      '#default_value' => (!empty($this->options['short_title'])) ? $this->options['short_title'] : '',
+    ];
     // Display settings.
     $form['display'] = [
       '#type' => 'details',