diff --git a/ui/client-app/src/App.js b/ui/client-app/src/App.js
index 8e60cd7..9a76f5b 100644
--- a/ui/client-app/src/App.js
+++ b/ui/client-app/src/App.js
@@ -156,7 +156,7 @@
           Icon={Icon}
         />
       )}
-      <div className="flex-grow overflow-y-auto scroll-smooth">
+      <div className="flex-grow overflow-hidden">
         {renderPage()}
       </div>
     </div>
diff --git a/ui/client-app/src/components/ChatArea.css b/ui/client-app/src/components/ChatArea.css
index 7481fed..0d86e34 100644
--- a/ui/client-app/src/components/ChatArea.css
+++ b/ui/client-app/src/components/ChatArea.css
@@ -1,5 +1,4 @@
-.chat-area-fixed-height {
-    height: calc(100vh - 72px); /* Subtract input + padding */
-  }
-
-  
\ No newline at end of file
+/* ChatArea styles moved to inline Tailwind where possible */
+.custom-scrollbar::-webkit-scrollbar {
+  width: 6px;
+}
\ No newline at end of file
diff --git a/ui/client-app/src/components/ChatArea.js b/ui/client-app/src/components/ChatArea.js
index e5172cc..3080fea 100644
--- a/ui/client-app/src/components/ChatArea.js
+++ b/ui/client-app/src/components/ChatArea.js
@@ -30,7 +30,7 @@
   }, [chatHistory]);
 
   return (
-    <div className="flex flex-col chat-area-fixed-height">
+    <div className="flex flex-col h-full">
       {/* Scrollable ChatWindow */}
       <div ref={chatScrollRef} className="flex-grow overflow-y-auto">
         <ChatWindow chatHistory={chatHistory} featureName={featureName} />
@@ -52,8 +52,8 @@
             type="submit"
             disabled={isProcessing}
             className={`p-3 rounded-lg text-white font-bold transition-colors flex-shrink-0 ${isProcessing
-                ? "bg-gray-400 dark:bg-gray-600 cursor-not-allowed"
-                : "bg-indigo-600 hover:bg-indigo-700"
+              ? "bg-gray-400 dark:bg-gray-600 cursor-not-allowed"
+              : "bg-indigo-600 hover:bg-indigo-700"
               }`}
           >
             Send
diff --git a/ui/client-app/src/components/SessionSidebar.js b/ui/client-app/src/components/SessionSidebar.js
index 964b02d..028a60d 100644
--- a/ui/client-app/src/components/SessionSidebar.js
+++ b/ui/client-app/src/components/SessionSidebar.js
@@ -12,6 +12,7 @@
     const [sessions, setSessions] = useState([]);
     const [tokenHoverData, setTokenHoverData] = useState({});
     const [isLoading, setIsLoading] = useState(false);
+    const [confirmModal, setConfirmModal] = useState({ isOpen: false, title: '', message: '', onConfirm: null });
 
     useEffect(() => {
         if (isOpen) fetchSessions();
@@ -37,26 +38,39 @@
         } catch (err) { /* silent */ }
     };
 
-    const handleDelete = async (e, sessionId) => {
+    const handleDelete = (e, sessionId) => {
         e.stopPropagation();
-        if (!window.confirm('Delete this session?')) return;
-        try {
-            await deleteSession(sessionId);
-            fetchSessions();
-            if (Number(currentSessionId) === sessionId) {
-                localStorage.removeItem(`sessionId_${featureName}`);
-                if (onNewSession) onNewSession();
+        setConfirmModal({
+            isOpen: true,
+            title: 'Delete Session',
+            message: 'Are you sure you want to delete this session? This action cannot be undone.',
+            onConfirm: async () => {
+                try {
+                    await deleteSession(sessionId);
+                    fetchSessions();
+                    if (Number(currentSessionId) === sessionId) {
+                        localStorage.removeItem(`sessionId_${featureName}`);
+                        if (onNewSession) onNewSession();
+                    }
+                } catch { alert('Failed to delete session.'); }
             }
-        } catch { alert('Failed to delete session.'); }
+        });
     };
 
-    const handleDeleteAll = async () => {
-        if (!window.confirm('Delete ALL history for this feature?')) return;
-        try {
-            await deleteAllSessions(featureName);
-            fetchSessions();
-            if (onNewSession) onNewSession();
-        } catch { alert('Failed to delete all sessions.'); }
+    const handleDeleteAll = (e) => {
+        if (e) e.stopPropagation();
+        setConfirmModal({
+            isOpen: true,
+            title: 'Clear All History',
+            message: 'Are you sure you want to delete ALL history for this feature? This action is permanent.',
+            onConfirm: async () => {
+                try {
+                    await deleteAllSessions(featureName);
+                    fetchSessions();
+                    if (onNewSession) onNewSession();
+                } catch { alert('Failed to delete all sessions.'); }
+            }
+        });
     };
 
     const formatDate = (iso) => {
@@ -86,7 +100,7 @@
                 <div className="sidebar-content">
                     <div className="sidebar-header">
                         <h3>{prettyFeatureName} History</h3>
-                        <button className="delete-all" onClick={handleDeleteAll}>
+                        <button type="button" className="delete-all" onClick={(e) => handleDeleteAll(e)}>
                             Clear All
                         </button>
                     </div>
@@ -134,6 +148,7 @@
                                             </div>
                                         </div>
                                         <button
+                                            type="button"
                                             className="sidebar-item-delete"
                                             onClick={(e) => handleDelete(e, s.id)}
                                             title="Delete this session"
@@ -147,6 +162,35 @@
                     </div>
                 </div>
             )}
+            {/* Custom Confirmation Modal */}
+            {confirmModal.isOpen && (
+                <div className="fixed inset-0 bg-gray-900/60 backdrop-blur-sm flex justify-center items-center z-[2000] animate-in fade-in duration-300 px-4">
+                    <div className="bg-white dark:bg-gray-800 p-8 rounded-2xl shadow-2xl max-w-sm w-full text-center border border-red-100 dark:border-red-900/30">
+                        <div className="w-16 h-16 bg-red-100 dark:bg-red-900/30 rounded-full flex items-center justify-center mx-auto mb-4">
+                            <svg className="w-8 h-8 text-red-600" fill="none" stroke="currentColor" viewBox="0 0 24 24"><path strokeLinecap="round" strokeLinejoin="round" strokeWidth="2" d="M19 7l-.867 12.142A2 2 0 0116.138 21H7.862a2 2 0 01-1.995-1.858L5 7m5 4v6m4-6v6m1-10V4a1 1 0 00-1-1h-4a1 1 0 00-1 1v3M4 7h16" /></svg>
+                        </div>
+                        <h2 className="text-xl font-bold mb-2 text-gray-900 dark:text-white">{confirmModal.title}</h2>
+                        <p className="text-gray-500 dark:text-gray-400 mb-6 text-sm">{confirmModal.message}</p>
+                        <div className="flex gap-3">
+                            <button
+                                onClick={() => setConfirmModal({ ...confirmModal, isOpen: false })}
+                                className="flex-1 bg-gray-100 dark:bg-gray-700 text-gray-700 dark:text-gray-300 font-bold py-3 rounded-xl transition-all active:scale-95 underline-none"
+                            >
+                                Cancel
+                            </button>
+                            <button
+                                onClick={() => {
+                                    confirmModal.onConfirm();
+                                    setConfirmModal({ ...confirmModal, isOpen: false });
+                                }}
+                                className="flex-1 bg-red-600 text-white font-bold py-3 rounded-xl transition-all shadow-lg shadow-red-500/20 active:scale-95 underline-none"
+                            >
+                                Delete
+                            </button>
+                        </div>
+                    </div>
+                </div>
+            )}
         </div>
     );
 };
diff --git a/ui/client-app/src/hooks/useCodeAssistant.js b/ui/client-app/src/hooks/useCodeAssistant.js
index ec8bcde..6353335 100644
--- a/ui/client-app/src/hooks/useCodeAssistant.js
+++ b/ui/client-app/src/hooks/useCodeAssistant.js
@@ -110,7 +110,9 @@
     if (text.trim().toLowerCase() === "/new") {
       setChatHistory([]);
       localStorage.removeItem("sessionId_coding_assistant");
-      const newSid = await getSessionId("coding_assistant", localActiveLLM || "gemini");
+      const prefProvider = userConfigData?.effective?.llm?.active_provider || "gemini";
+      const newSid = await getSessionId("coding_assistant", prefProvider);
+      setLocalActiveLLM(prefProvider);
       setSessionId(newSid);
       sessionIdRef.current = newSid;
       fetchTokenUsage();
diff --git a/ui/client-app/src/hooks/useVoiceChat.js b/ui/client-app/src/hooks/useVoiceChat.js
index b003ac6..3564e91 100644
--- a/ui/client-app/src/hooks/useVoiceChat.js
+++ b/ui/client-app/src/hooks/useVoiceChat.js
@@ -455,14 +455,24 @@
     try {
       const audioDuration = audioBlob.size / (48000 * 2 * 1) * 1000;
       if (audioDuration < MINIMUM_AUDIO_DURATION_MS) {
+        const msg = "Your recording was too short. Please speak for at least half a second.";
         console.log(`Audio too short (${audioDuration.toFixed(2)}ms), skipping.`);
-        setStatus("Audio was too short. Please speak a little longer.");
+        setStatus(msg);
+        if (!isAutoMode) {
+          setErrorMessage(msg);
+          setShowErrorModal(true);
+        }
         lastRequestTimeRef.current = Date.now();
         return;
       }
       if (audioBlob.size === 0) {
+        const msg = "Recording stopped, but no audio was captured. Please try again.";
         console.warn("Audio blob is empty, skipping STT API call.");
-        setStatus("Recording stopped, but no audio was captured. Please try again.");
+        setStatus(msg);
+        if (!isAutoMode) {
+          setErrorMessage(msg);
+          setShowErrorModal(true);
+        }
         lastRequestTimeRef.current = Date.now();
         return;
       }
@@ -670,11 +680,13 @@
 
     setIsBusy(true);
     setStatus("Starting new session...");
+    const prefProvider = userConfigData?.effective?.llm?.active_provider || "gemini";
     try {
-      const newSessionId = await getSessionId("voice_chat", localActivePrefs.llm || "gemini", {
-        stt_provider_name: localActivePrefs.stt,
-        tts_provider_name: localActivePrefs.tts
+      const newSessionId = await getSessionId("voice_chat", prefProvider, {
+        stt_provider_name: localActivePrefs.stt || userConfigData?.effective?.stt?.active_provider,
+        tts_provider_name: localActivePrefs.tts || userConfigData?.effective?.tts?.active_provider
       });
+      setLocalActivePrefs(prev => ({ ...prev, llm: prefProvider }));
       setSessionId(newSessionId);
       sessionIdRef.current = newSessionId;
       fetchTokenUsage();
diff --git a/ui/client-app/src/pages/CodingAssistantPage.js b/ui/client-app/src/pages/CodingAssistantPage.js
index eed9113..56659bc 100644
--- a/ui/client-app/src/pages/CodingAssistantPage.js
+++ b/ui/client-app/src/pages/CodingAssistantPage.js
@@ -46,7 +46,7 @@
   }, [chatHistory]);
 
   return (
-    <div className="flex flex-col flex-grow h-full min-h-screen bg-gray-100 dark:bg-gray-900 text-gray-900 dark:text-gray-100 relative">
+    <div className="flex flex-col flex-grow h-full overflow-hidden bg-gray-100 dark:bg-gray-900 text-gray-900 dark:text-gray-100 relative">
       <SessionSidebar
         featureName="coding_assistant"
         currentSessionId={sessionId}
@@ -56,11 +56,11 @@
       />
 
       {/* Main content area */}
-      <div className="flex-grow px-4 overflow-hidden" ref={pageContainerRef}>
-        <div className="max-w-4xl mx-auto h-full py-4">
+      <div className="flex-grow flex flex-col px-4 min-h-0" ref={pageContainerRef}>
+        <div className="max-w-4xl mx-auto w-full h-full pt-12 pb-8 flex flex-col min-h-0">
           {/* Chat Area */}
-          <div className="flex flex-col h-full">
-            <div className="flex-grow p-4 bg-white dark:bg-gray-800 rounded-xl shadow-lg border border-gray-200 dark:border-gray-700 flex flex-col">
+          <div className="flex flex-col h-full min-h-0">
+            <div className="flex-grow p-4 bg-white dark:bg-gray-800 rounded-xl shadow-lg border border-gray-200 dark:border-gray-700 flex flex-col min-h-0">
               <h2 className="text-xl font-bold mb-4 flex justify-between items-center border-b border-gray-100 dark:border-gray-700 pb-4">
                 <div className="flex items-center gap-3">
                   <div className="p-2 bg-indigo-100 dark:bg-indigo-900/30 rounded-lg">
@@ -113,12 +113,12 @@
                     onClick={() => handleSendChat("/new")}
                     className="text-xs font-bold px-4 py-2 bg-indigo-600 hover:bg-indigo-700 text-white rounded-lg transition-all shadow-md hover:shadow-indigo-500/20 active:scale-95"
                   >
-                    + NEW CHAT
+                    + NEW SESSION
                   </button>
                 </div>
               </h2>
 
-              <div className="flex-grow overflow-hidden flex flex-col">
+              <div className="flex-grow flex flex-col min-h-0">
                 <ChatArea
                   chatHistory={chatHistory}
                   onSendMessage={handleSendChat}
diff --git a/ui/client-app/src/pages/HomePage.js b/ui/client-app/src/pages/HomePage.js
index 6be1510..e095251 100644
--- a/ui/client-app/src/pages/HomePage.js
+++ b/ui/client-app/src/pages/HomePage.js
@@ -19,7 +19,7 @@
   };
 
   return (
-    <div className="flex flex-col items-center justify-center min-h-screen bg-gray-100 dark:bg-gray-900 text-gray-900 dark:text-gray-100 p-4">
+    <div className="flex flex-col items-center justify-center h-full overflow-y-auto bg-gray-100 dark:bg-gray-900 text-gray-900 dark:text-gray-100 p-4">
       <div className="bg-white dark:bg-gray-800 p-8 sm:p-12 rounded-lg shadow-xl text-center max-w-2xl w-full">
         <h1 className="text-4xl font-bold text-blue-600 dark:text-blue-400 mb-4">
           Welcome to Cortex AI! 🧠
diff --git a/ui/client-app/src/pages/SettingsPage.js b/ui/client-app/src/pages/SettingsPage.js
index 08034db..0833dfe 100644
--- a/ui/client-app/src/pages/SettingsPage.js
+++ b/ui/client-app/src/pages/SettingsPage.js
@@ -870,7 +870,7 @@
     });
 
     return (
-        <div className="py-10 px-4 sm:px-6 lg:px-8 font-sans">
+        <div className="h-full overflow-y-auto py-10 px-4 sm:px-6 lg:px-8 font-sans">
             <div className="max-w-3xl mx-auto">
                 <div className="flex justify-between items-end mb-2">
                     <h1 className="text-3xl font-extrabold text-gray-900 dark:text-white tracking-tight">Configuration</h1>
diff --git a/ui/client-app/src/pages/VoiceChatPage.js b/ui/client-app/src/pages/VoiceChatPage.js
index ada91a9..7f0562f 100644
--- a/ui/client-app/src/pages/VoiceChatPage.js
+++ b/ui/client-app/src/pages/VoiceChatPage.js
@@ -66,7 +66,7 @@
   };
 
   return (
-    <div className="flex flex-col flex-grow h-full min-h-screen bg-gray-100 dark:bg-gray-900 text-gray-900 dark:text-gray-100 relative overflow-hidden">
+    <div className="flex flex-col flex-grow h-full overflow-hidden bg-gray-100 dark:bg-gray-900 text-gray-900 dark:text-gray-100 relative">
       <SessionSidebar
         featureName="voice_chat"
         currentSessionId={sessionId}
@@ -76,11 +76,11 @@
       />
 
       {/* Main content area */}
-      <div className="flex-grow px-4 overflow-hidden" ref={chatContainerRef}>
-        <div className="max-w-4xl mx-auto h-full py-4">
+      <div className="flex-grow flex flex-col px-4 min-h-0" ref={chatContainerRef}>
+        <div className="max-w-4xl mx-auto w-full h-full pt-12 pb-8 flex flex-col min-h-0">
           {/* Chat Area Box */}
-          <div className="flex flex-col h-full">
-            <div className="flex-grow p-4 bg-white dark:bg-gray-800 rounded-xl shadow-lg border border-gray-200 dark:border-gray-700 flex flex-col overflow-hidden">
+          <div className="flex flex-col h-full min-h-0">
+            <div className="flex-grow p-4 bg-white dark:bg-gray-800 rounded-xl shadow-lg border border-gray-200 dark:border-gray-700 flex flex-col min-h-0">
 
               {/* Box Header */}
               <h2 className="text-xl font-bold mb-4 flex justify-between items-center border-b border-gray-100 dark:border-gray-700 pb-4">
diff --git a/ui/client-app/src/services/apiService.js b/ui/client-app/src/services/apiService.js
index 98ea236..5bce459 100644
--- a/ui/client-app/src/services/apiService.js
+++ b/ui/client-app/src/services/apiService.js
@@ -118,7 +118,7 @@
  */
 export const getUserSessions = async (featureName = "default") => {
   const userId = getUserId();
-  const params = new URLSearchParams({ user_id: userId, feature_name: featureName });
+  const params = new URLSearchParams({ user_id: userId, feature_name: featureName, _t: Date.now() });
   const response = await fetch(`${SESSIONS_GET_ALL_ENDPOINT}?${params.toString()}`, {
     method: "GET",
     headers: { "X-User-ID": userId },
@@ -223,7 +223,7 @@
  */
 export const deleteAllSessions = async (featureName = "default") => {
   const userId = getUserId();
-  const params = new URLSearchParams({ user_id: userId, feature_name: featureName });
+  const params = new URLSearchParams({ user_id: userId, feature_name: featureName, _t: Date.now() });
   const response = await fetch(`${SESSIONS_GET_ALL_ENDPOINT}?${params.toString()}`, {
     method: "DELETE",
     headers: { "X-User-ID": userId },