Fix scroll-to-bottom in builder page

- Simplified scrollChatToBottom() with more reliable techniques
- Added scrollIntoView on last message as fallback
- Added additional scroll with direct scrollTop assignment after delay
- Added CSS optimizations for scrolling behavior (-webkit-overflow-scrolling, transform, will-change)
- Added more robust scroll attempts in renderMessages after DOM updates

chat/public/builder.html

@@ -55,6 +55,10 @@
       flex: 1;
       overflow-y: auto;
       min-height: 0;
+      -webkit-overflow-scrolling: touch;
+      scroll-behavior: auto;
+      transform: translateZ(0);
+      will-change: scroll-position;
     }
 
     .app-shell.builder-single>* {

chat/public/builder.js

@@ -1520,7 +1520,7 @@ function closeHistoryModal() {
   if (el.historyModal) el.historyModal.style.display = 'none';
 }
 
-function scrollChatToBottom(force = false) {
+function scrollChatToBottom() {
   if (!el.chatArea) return;
   const target = el.chatArea;
   
@@ -1529,91 +1529,48 @@ function scrollChatToBottom(force = false) {
     target.scrollTop = target.scrollHeight;
   };
 
-  // Use multiple techniques to ensure scroll happens after content is rendered
+  // Use multiple scroll techniques in sequence for reliability
-  // 1. Immediate scroll attempt
+  // 1. Immediate scroll
   doScroll();
   
-  // 2. After short delays to allow DOM updates
+  // 2. After DOM updates
-  setTimeout(() => { doScroll(); }, 10);
+  setTimeout(doScroll, 50);
-  setTimeout(() => { doScroll(); }, 50);
+  setTimeout(doScroll, 100);
-  setTimeout(() => { doScroll(); }, 100);
+  setTimeout(doScroll, 200);
-  setTimeout(() => { doScroll(); }, 250);
+  setTimeout(doScroll, 500);
-  setTimeout(() => { doScroll(); }, 500);
   
-  // 3. Longer delay for content to fully settle (especially on page load)
+  // 3. After content fully renders
-  setTimeout(() => { doScroll(); }, 1000);
+  setTimeout(doScroll, 1000);
-  setTimeout(() => { doScroll(); }, 2000);
   
-  // 4. Use requestAnimationFrame for smooth scrolling
+  // 4. requestAnimationFrame for smooth scrolling
   requestAnimationFrame(() => {
     doScroll();
-    requestAnimationFrame(() => {
+    requestAnimationFrame(doScroll);
-      doScroll();
-      requestAnimationFrame(() => {
-        doScroll();
-      });
-    });
   });
 
-  // 5. Wait for ALL images to load before scrolling
+  // 5. Scroll to last message element if it exists (most reliable method)
-  const images = target.querySelectorAll('img');
+  setTimeout(() => {
-  let imagesToLoad = 0;
+    const lastMessage = target.querySelector('.message:last-child');
-  
+    if (lastMessage) {
-  images.forEach((img) => {
+      lastMessage.scrollIntoView({ behavior: 'smooth', block: 'end' });
-    if (!img.complete) {
+    } else {
-      imagesToLoad++;
+      // Fallback to regular scroll
-      img.addEventListener('load', () => {
-        imagesToLoad--;
       doScroll();
-        // Scroll again after a short delay to ensure layout is updated
-        setTimeout(() => doScroll(), 100);
-      }, { once: true });
-      
-      img.addEventListener('error', () => {
-        imagesToLoad--;
-        doScroll();
-      }, { once: true });
-    }
-  });
-  
-  // If there are images loading, scroll again after they all complete
-  if (imagesToLoad > 0) {
-    const checkImagesLoaded = setInterval(() => {
-      if (imagesToLoad === 0) {
-        clearInterval(checkImagesLoaded);
-        doScroll();
-        setTimeout(() => doScroll(), 100);
-        setTimeout(() => doScroll(), 500);
     }
   }, 100);
 
-    // Stop checking after 5 seconds to avoid infinite interval
+  // 6. ResizeObserver for dynamic content
-    setTimeout(() => clearInterval(checkImagesLoaded), 5000);
-  }
-  
-  // 6. Use ResizeObserver to detect when content height changes
   if (typeof ResizeObserver !== 'undefined') {
-    const resizeObserver = new ResizeObserver((entries) => {
+    const resizeObserver = new ResizeObserver(() => doScroll());
-      for (const entry of entries) {
-        if (entry.target === target) {
-          doScroll();
-        }
-      }
-    });
     resizeObserver.observe(target);
-    
+    setTimeout(() => resizeObserver.disconnect(), 2000);
-    // Stop observing after a while
-    setTimeout(() => resizeObserver.disconnect(), 3000);
   }
 
-  // 7. Also scroll when any content finishes rendering (using MutationObserver)
+  // 7. MutationObserver for DOM changes
   if (typeof MutationObserver !== 'undefined') {
-    const observer = new MutationObserver(() => {
+    const observer = new MutationObserver(() => doScroll());
-      doScroll();
-    });
     observer.observe(target, { childList: true, subtree: true });
-    // Stop observing after a while to avoid memory leaks
+    setTimeout(() => observer.disconnect(), 2000);
-    setTimeout(() => observer.disconnect(), 3000);
   }
 }
 
@@ -2027,8 +1984,23 @@ function renderMessages(session) {
     }
   }
 
+  // Scroll to bottom after DOM updates
   scrollChatToBottom();
   
+  // Additional scroll with longer delay to ensure all content is rendered
+  setTimeout(() => {
+    scrollChatToBottom();
+    // Force scroll by accessing scrollHeight directly
+    if (el.chatArea) {
+      el.chatArea.scrollTop = el.chatArea.scrollHeight;
+      // Scroll last element into view as fallback
+      const lastMessage = el.chatArea.querySelector('.message:last-child');
+      if (lastMessage) {
+        lastMessage.scrollIntoView({ block: 'end' });
+      }
+    }
+  }, 200);
+
   updateExportButtonVisibility(session);
 }