Bug-fix.

Changelog excerpt:
- When changing the front-end's theme or theme mode at the configuration
  page, the change wasn't being seen immediately, instead being seen only
  upon subsequent request to any front-end page; Fixed.

Author: Maikuolan

Changelog.md

@@ -199,6 +199,7 @@ __*Why "v3.0.0" instead of "v1.0.0?"*__ Prior to phpMussel v3, the "phpMussel Co
 #### Bugs fixed.
 - [2025.07.07]: The formatFilesize method wasn't accounting for negative numbers; Fixed.
 - [2025.07.26]: Some browsers, in some contexts, were raising errors during request inspection concerning the absence of any X-Content-Type-Options header declaration (though it isn't entirely clear whether this error had any actual effect); Fixed.
+- [2025.08.09]: When changing the front-end's theme or theme mode at the configuration page, the change wasn't being seen immediately, instead being seen only upon subsequent request to any front-end page; Fixed.
 
 #### Security.
 - [2025.08.09]: Improved the safeguards for getAssetPath.

src/FrontEnd.php

@@ -330,9 +330,16 @@ public function view(string $Page = ''): void
             'FormTarget' => $_POST['phpmussel-form-target'] ?? ''
         ];
 
-        /** Fix for immediate display of freshly updated theme selection. */
-        if (!empty($_POST['config_frontend_theme']) && !preg_match('~[^a-z]~', $_POST['config_frontend_theme']) && ($_POST['config_frontend_theme'] === 'default' ?: file_exists($this->AssetsPath . $_POST['config_frontend_theme'] . DIRECTORY_SEPARATOR . 'frontend.css'))) {
-            $FE['theme'] = $_POST['config_frontend_theme'];
+        if ($Page === 'config') {
+            /** Fix for immediate display of freshly updated theme selection. */
+            if (!empty($_POST['config_frontend_theme']) && !preg_match('~[^a-z]~', $_POST['config_frontend_theme']) && ($_POST['config_frontend_theme'] === 'default' ?: file_exists($this->AssetsPath . $_POST['config_frontend_theme'] . DIRECTORY_SEPARATOR . 'frontend.css'))) {
+                $FE['theme'] = $_POST['config_frontend_theme'];
+            }
+
+            /** Fix for immediate display of freshly updated theme mode selection. */
+            if (!empty($_POST['config_frontend_theme_mode']) && isset($this->Loader->ConfigurationDefaults['frontend']['theme_mode']['choices'][$_POST['config_frontend_theme_mode']])) {
+                $FE['theme_mode'] = $_POST['config_frontend_theme_mode'];
+            }
         }
 
         /** Populated by [Home | Log Out] by default; Replaced by [Log Out] for some specific pages (e.g., the homepage). */