Fix selected option highlighting in theme menu.

module/VuFindTheme/src/VuFindTheme/Initializer.php

@@ -167,8 +167,10 @@ public function init()
             isset($this->event) ? $this->event->getRequest() : null
         );
 
-        // Determine theme options:
-        $this->sendThemeOptionsToView($currentTheme);
+        // Determine theme options (note that we should use the ui cookie rather
+        // than the raw theme name, since options include aliases, and we want the
+        // user-selected alias, not the final resolved theme name):
+        $this->sendThemeOptionsToView($this->cookieManager->get('ui'));
 
         // Make sure the current theme is set correctly in the tools object:
         $error = null;
@@ -303,14 +305,29 @@ protected function getThemeOptions($currentTheme)
         $options = [];
         if (isset($this->config->selectable_themes)) {
             $parts = explode(',', $this->config->selectable_themes);
+
+            if (isset($this->config->alternate_themes)) {
+                $aliases = explode(',', $this->config->alternate_themes);
+            }
+
             foreach ($parts as $part) {
                 $subparts = explode(':', $part);
-                $name = trim($subparts[0]);
+                $displayName = $name = trim($subparts[0]);
                 $desc = isset($subparts[1]) ? trim($subparts[1]) : '';
-                $desc = empty($desc) ? $name : $desc;
+                $desc = empty($desc) ? $displayName : $desc;
+
+                if (!empty($aliases)) {
+                    $key = array_search("{$name}:{$currentTheme}", $aliases);
+
+                    if ($key !== false) {
+                        $name = $currentTheme;
+                    }
+                }
+
                 if (!empty($name)) {
                     $options[] = [
-                        'name' => $name, 'desc' => $desc,
+                        'name' => $displayName,
+                        'desc' => $desc,
                         'selected' => ($currentTheme == $name),
                     ];
                 }