diff --git a/calendar/inc/class.calendar_bo.inc.php b/calendar/inc/class.calendar_bo.inc.php
index e289685a1d..cfe6626d28 100644
--- a/calendar/inc/class.calendar_bo.inc.php
+++ b/calendar/inc/class.calendar_bo.inc.php
@@ -731,15 +731,16 @@ class calendar_bo
 	 *
 	 * @param string $app
 	 * @param string $part
+	 * @param boole $try_load=false true: load if not yet loaded
 	 * @return array
 	 */
-	static function integration_get_data($app,$part=null)
+	static function integration_get_data($app, $part=null, $try_load=false)
 	{
 		static $integration_data=null;
 
 		if (!isset($integration_data))
 		{
-			$integration_data = calendar_so::get_integration_data();
+			$integration_data = calendar_so::get_integration_data($try_load);
 		}
 
 		if (!isset($integration_data[$app])) return null;
@@ -747,6 +748,25 @@ class calendar_bo
 		return $part ? $integration_data[$app][$part] : $integration_data[$app];
 	}
 
+	/**
+	 * Check if an integration event is deletable
+	 *
+	 * @param string $app
+	 * @param array $event
+	 * @return bool
+	 */
+	static function integration_deletable($app, array $event)
+	{
+		$app_data = self::integration_get_data($app,'deletable');
+
+		if (empty($app_data) || is_bool($app_data))
+		{
+			return (bool)$app_data;
+		}
+
+		return (bool)(is_callable($app_data) ? $app_data($event) : ExecMethod2($app_data, $event));
+	}
+
 	/**
 	 * Get private attribute for an integration event
 	 *
diff --git a/calendar/inc/class.calendar_so.inc.php b/calendar/inc/class.calendar_so.inc.php
index ded116502b..787d2d2824 100644
--- a/calendar/inc/class.calendar_so.inc.php
+++ b/calendar/inc/class.calendar_so.inc.php
@@ -1244,10 +1244,16 @@ class calendar_so
 	/**
 	 * Get data from last 'calendar_search_union' hook call
 	 *
-	 * @return array
+	 * @param boole $try_load=false true: load if not yet loaded
+	 * @return ?array
 	 */
-	public static function get_integration_data()
+	public static function get_integration_data($try_load=false)
 	{
+		if (!isset(self::$integration_data) && $try_load)
+		{
+			$selects = [];
+			self::get_union_selects($selects, 0, 0, [$GLOBALS['egw_info']['user']['account_id']], 0, [], '', [$GLOBALS['egw_info']['user']['account_id']]);
+		}
 		return self::$integration_data;
 	}
 
diff --git a/calendar/inc/class.calendar_ui.inc.php b/calendar/inc/class.calendar_ui.inc.php
index 44ed9d7552..a545d8a247 100644
--- a/calendar/inc/class.calendar_ui.inc.php
+++ b/calendar/inc/class.calendar_ui.inc.php
@@ -731,13 +731,12 @@ class calendar_ui
 
 		static $sent_groups = array();
 
-		if (!$this->bo->check_perms(Acl::EDIT,$event))
+		if (!is_numeric($event['id']) || !$this->bo->check_perms(Acl::EDIT,$event))
 		{
 			$event['class'] .= 'rowNoEdit ';
 		}
 
-		// Delete disabled for other applications
-		if (!$this->bo->check_perms(Acl::DELETE,$event) || !is_numeric($event['id']))
+		if (is_numeric($event['id']) && !$this->bo->check_perms(Acl::DELETE, $event))
 		{
 			$event['class'] .= 'rowNoDelete ';
 		}
@@ -772,6 +771,11 @@ class calendar_ui
 			}
 			$event['app'] = $app;
 			$event['app_id'] = $app_id;
+			// check if integration-app allows/supports delete
+			if (!calendar_bo::integration_deletable($app, $event))
+			{
+				$event['class'] .= 'rowNoDelete';
+			}
 		}
 		else
 		{
diff --git a/calendar/inc/class.calendar_uiforms.inc.php b/calendar/inc/class.calendar_uiforms.inc.php
index bb7544195d..6d186cbe93 100644
--- a/calendar/inc/class.calendar_uiforms.inc.php
+++ b/calendar/inc/class.calendar_uiforms.inc.php
@@ -3261,9 +3261,22 @@ class calendar_uiforms extends calendar_ui
 	 */
 	public function ajax_delete($eventId)
 	{
-		list($id, $date) = explode(':',$eventId);
-		$event=$this->bo->read($id);
 		$response = Api\Json\Response::get();
+		list($id, $date) = explode(':',$eventId);
+		// let integration take care of delete for integration-events
+		if (!is_numeric($id) && preg_match('/^([^\d]+)(\d+)$/', $id, $matches) &&
+			!empty($app_data = calendar_bo::integration_get_data($matches[1], 'delete', true)))
+		{
+			try {
+				$msg = is_callable($app_data) ? $app_data($matches[2]) : ExecMethod2($app_data, $matches[2]);
+				$response->call('egw.refresh', $msg, 'calendar', $eventId, 'delete');
+			}
+			catch (\Exception $e) {
+				$response->apply('egw.message', $e->getMessage(), 'error');
+			}
+			return;
+		}
+		$event=$this->bo->read($id);
 
 		if ($this->bo->delete($event['id'], (int)$date))
 		{