diff --git a/public/index.html b/public/index.html
index 0a4f008f0..3835913a8 100644
--- a/public/index.html
+++ b/public/index.html
@@ -3310,7 +3310,7 @@
                                 <h4 data-i18n="Google Model">Google Model</h4>
                                 <select id="model_vertexai_select">
                                     <!-- Express Mode Models -->
-                                    <optgroup id="vertexai_express_models" label="Express Mode Models">
+                                    <optgroup id="vertexai_express_models" label="Express Mode Models" data-mode="express">
                                         <option value="gemini-2.5-pro-preview-05-06">gemini-2.5-pro-preview-05-06</option>
                                         <option value="gemini-2.5-pro-preview-03-25">gemini-2.5-pro-preview-03-25</option>
                                         <option value="gemini-2.5-flash-preview-05-20">gemini-2.5-flash-preview-05-20</option>
@@ -3320,14 +3320,14 @@
                                     </optgroup>
 
                                     <!-- Full Version Models -->
-                                    <optgroup id="vertexai_full_gemini_25" label="Gemini 2.5" style="display: none;">
+                                    <optgroup id="vertexai_full_gemini_25" label="Gemini 2.5" data-mode="full" style="display: none;">
                                         <option value="gemini-2.5-pro-preview-05-06">gemini-2.5-pro-preview-05-06</option>
                                         <option value="gemini-2.5-pro-preview-03-25">gemini-2.5-pro-preview-03-25</option>
                                         <option value="gemini-2.5-pro-exp-03-25">gemini-2.5-pro-exp-03-25</option>
                                         <option value="gemini-2.5-flash-preview-05-20">gemini-2.5-flash-preview-05-20</option>
                                         <option value="gemini-2.5-flash-preview-04-17">gemini-2.5-flash-preview-04-17</option>
                                     </optgroup>
-                                    <optgroup id="vertexai_full_gemini_20" label="Gemini 2.0" style="display: none;">
+                                    <optgroup id="vertexai_full_gemini_20" label="Gemini 2.0" data-mode="full" style="display: none;">
                                         <option value="gemini-2.0-pro-exp-02-05">gemini-2.0-pro-exp-02-05 → 2.5-pro-exp-03-25</option>
                                         <option value="gemini-2.0-pro-exp">gemini-2.0-pro-exp → 2.5-pro-exp-03-25</option>
                                         <option value="gemini-exp-1206">gemini-exp-1206 → 2.5-pro-exp-03-25</option>
@@ -3342,7 +3342,7 @@
                                         <option value="gemini-2.0-flash-lite-preview-02-05">gemini-2.0-flash-lite-preview-02-05</option>
                                         <option value="gemini-2.0-flash-lite-preview">gemini-2.0-flash-lite-preview</option>
                                     </optgroup>
-                                    <optgroup id="vertexai_full_gemini_15" label="Gemini 1.5" style="display: none;">
+                                    <optgroup id="vertexai_full_gemini_15" label="Gemini 1.5" data-mode="full" style="display: none;">
                                         <option value="gemini-1.5-pro-latest">gemini-1.5-pro-latest</option>
                                         <option value="gemini-1.5-pro-002">gemini-1.5-pro-002</option>
                                         <option value="gemini-1.5-pro-001">gemini-1.5-pro-001</option>
@@ -3356,13 +3356,13 @@
                                         <option value="gemini-1.5-flash-8b-exp-0827">gemini-1.5-flash-8b-exp-0827</option>
                                         <option value="gemini-1.5-flash-8b">gemini-1.5-flash-8b</option>
                                     </optgroup>
-                                    <optgroup id="vertexai_full_gemma" label="Gemma" style="display: none;">
+                                    <optgroup id="vertexai_full_gemma" label="Gemma" data-mode="full" style="display: none;">
                                         <option value="gemma-3-27b-it">gemma-3-27b-it</option>
                                         <option value="gemma-3-12b-it">gemma-3-12b-it</option>
                                         <option value="gemma-3-4b-it">gemma-3-4b-it</option>
                                         <option value="gemma-3-1b-it">gemma-3-1b-it</option>
                                     </optgroup>
-                                    <optgroup id="vertexai_full_learnlm" label="LearnLM" style="display: none;">
+                                    <optgroup id="vertexai_full_learnlm" label="LearnLM" data-mode="full" style="display: none;">
                                         <option value="learnlm-2.0-flash-experimental">learnlm-2.0-flash-experimental</option>
                                         <option value="learnlm-1.5-pro-experimental">learnlm-1.5-pro-experimental</option>
                                     </optgroup>
diff --git a/public/scripts/openai.js b/public/scripts/openai.js
index f06eeb0f1..1deb246ca 100644
--- a/public/scripts/openai.js
+++ b/public/scripts/openai.js
@@ -5538,23 +5538,15 @@ function onVertexAIAuthModeChange() {
     if (authMode === 'express') {
         $('#vertexai_express_config').show();
         $('#vertexai_full_config').hide();
-        $('#vertexai_express_models').show();
-        // Hide all full version model groups
-        $('#vertexai_full_gemini_25').hide();
-        $('#vertexai_full_gemini_20').hide();
-        $('#vertexai_full_gemini_15').hide();
-        $('#vertexai_full_gemma').hide();
-        $('#vertexai_full_learnlm').hide();
+        // Show express mode model groups and hide full version model groups
+        $('#model_vertexai_select optgroup[data-mode="express"]').show();
+        $('#model_vertexai_select optgroup[data-mode="full"]').hide();
     } else {
         $('#vertexai_express_config').hide();
         $('#vertexai_full_config').show();
-        $('#vertexai_express_models').hide();
-        // Show all full version model groups
-        $('#vertexai_full_gemini_25').show();
-        $('#vertexai_full_gemini_20').show();
-        $('#vertexai_full_gemini_15').show();
-        $('#vertexai_full_gemma').show();
-        $('#vertexai_full_learnlm').show();
+        // Hide express mode model groups and show full version model groups
+        $('#model_vertexai_select optgroup[data-mode="express"]').hide();
+        $('#model_vertexai_select optgroup[data-mode="full"]').show();
     }
 
     saveSettingsDebounced();