[BUGFIX] Add better restriction to show view for preselected records

If singleRecords is filled, the displayMode is set to single and no
override is allowed, the record is always taken from the singleRecords
field.

Resolves: #578

Classes/Controller/AddressController.php

@@ -49,7 +49,9 @@ public function initializeAction(): void
 
     public function showAction(?Address $address = null)
     {
-        if (is_a($address, Address::class) && ($this->settings['detail']['checkPidOfAddressRecord'] ?? false)) {
+        if ((int)($this->settings['singleRecords'] ?? 0) && !($this->settings['allowOverride'] ?? false) && ($this->settings['displayMode'] ?? '' === 'single')) {
+            $address = $this->addressRepository->findByUid($this->settings['singleRecords']);
+        } elseif (is_a($address, Address::class) && ($this->settings['detail']['checkPidOfAddressRecord'] ?? false)) {
             $address = $this->checkPidOfAddressRecord($address);
         }