From 83b527211ff4526103bf487829ed33a975a7a797 Mon Sep 17 00:00:00 2001
From: Christian Rey Villablanca <chriztiann.villablanca@gmail.com>
Date: Tue, 4 Aug 2026 13:50:58 +0800
Subject: [PATCH] fix(chat): retain expanded preview collapse state

---
 tests/regression/chat-css-regression.test.mjs | 8 ++++++++
 webview/shared/src/chat/MessageComponents.tsx | 3 ++-
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/tests/regression/chat-css-regression.test.mjs b/tests/regression/chat-css-regression.test.mjs
index 08564fb..1d80998 100644
--- a/tests/regression/chat-css-regression.test.mjs
+++ b/tests/regression/chat-css-regression.test.mjs
@@ -153,6 +153,14 @@ test('response previews stay contained inside activity cards', () => {
   );
 });
 
+test('expanded response previews retain their collapse control', () => {
+  assert.match(
+    messageComponentsSource,
+    /if \(!preview\) \{\s*setHasResponseOverflow\(false\);\s*return;\s*}\s*if \(!shouldConstrainResponsePreview\) return;/s,
+    'expanding a response must preserve its measured overflow state so Show less remains available',
+  );
+});
+
 // ── Markdown list styling regression tests ───────────────────────────────────────
 
 test('markdown-body ordered lists must display with decimal numbers (not bullets)', () => {
diff --git a/webview/shared/src/chat/MessageComponents.tsx b/webview/shared/src/chat/MessageComponents.tsx
index 1129ff8..ecd5483 100644
--- a/webview/shared/src/chat/MessageComponents.tsx
+++ b/webview/shared/src/chat/MessageComponents.tsx
@@ -11723,10 +11723,11 @@ const hasVisibleResponseSectionContent =
 
   useEffect(() => {
     const preview = responsePreviewRef.current;
-    if (!preview || !shouldConstrainResponsePreview) {
+    if (!preview) {
       setHasResponseOverflow(false);
       return;
     }
+    if (!shouldConstrainResponsePreview) return;
 
     const updateOverflow = () => {
       const nextHasOverflow = preview.scrollHeight > preview.clientHeight + 1;