diff --git a/src/Resources/contao/dca/tl_calendar_events.php b/src/Resources/contao/dca/tl_calendar_events.php
index 7e39f97b60..565c844516 100644
--- a/src/Resources/contao/dca/tl_calendar_events.php
+++ b/src/Resources/contao/dca/tl_calendar_events.php
@@ -994,8 +994,15 @@ public function toggleVisibility($intId, $blnVisible)
 		{
 			foreach ($GLOBALS['TL_DCA']['tl_calendar_events']['fields']['published']['save_callback'] as $callback)
 			{
-				$this->import($callback[0]);
-				$blnVisible = $this->$callback[0]->$callback[1]($blnVisible, $this);
+				if (is_array($callback))
+				{
+					$this->import($callback[0]);
+					$blnVisible = $this->$callback[0]->$callback[1]($blnVisible, $this);
+				}
+				elseif (is_callable($callback))
+				{
+					$blnVisible = $callback($blnVisible, $this);
+				}
 			}
 		}