From e8b8e20eaae24b71ab0d9936c602d231345040a5 Mon Sep 17 00:00:00 2001
From: Eve <92513238+1320209572@users.noreply.github.com>
Date: Tue, 8 Sep 2026 16:48:47 +0800
Subject: [PATCH] fix(editor): isolate new query tab position

---
 .../src/components/editor/QueryEditor.vue       | 17 +++++++++--------
 .../editorTabSwitchViewportRestore.test.ts      | 10 ++++++++--
 2 files changed, 17 insertions(+), 10 deletions(-)

diff --git a/apps/desktop/src/components/editor/QueryEditor.vue b/apps/desktop/src/components/editor/QueryEditor.vue
index b6fa5d40f5..dae590cbcb 100644
--- a/apps/desktop/src/components/editor/QueryEditor.vue
+++ b/apps/desktop/src/components/editor/QueryEditor.vue
@@ -6709,8 +6709,10 @@ function activateTabDocument(prevTabId: string | undefined, tabId: string | unde
     // beyond MAX_CACHED_TAB_STATES): restore the tab's saved cursor and scroll
     // position exactly like the cached-state branch, otherwise the swapped-in
     // document keeps whatever scroll offset the dispatch left behind (#8374).
-    restoreEditorSelection();
-    restoreEditorViewport();
+    // A brand-new tab has no saved state, so reset it instead of falling back
+    // to the previous tab's latest position (#8378).
+    restoreEditorSelection(props.initialSelection ?? { anchor: 0, head: 0 });
+    restoreEditorViewport(props.initialViewport ?? { scrollTop: 0, scrollLeft: 0 });
     return;
   }
   // setState swaps doc, selection, undo history and all fields at once, but it
@@ -7066,10 +7068,10 @@ function flushEditorSelection() {
   if (latestSelection) emitEditorSelection(latestSelection);
 }
 
-function restoreEditorSelection() {
-  const selection = normalizedEditorSelection(props.initialSelection ?? latestSelection, props.modelValue.length);
-  if (!view.value || !selection) return;
-  view.value.dispatch({ selection });
+function restoreEditorSelection(selection = props.initialSelection ?? latestSelection) {
+  const normalizedSelection = normalizedEditorSelection(selection, props.modelValue.length);
+  if (!view.value || !normalizedSelection) return;
+  view.value.dispatch({ selection: normalizedSelection });
 }
 
 function restoreEditorFocus() {
@@ -7108,8 +7110,7 @@ function flushEditorViewport() {
   if (latestViewport) emitEditorViewport(latestViewport);
 }
 
-function restoreEditorViewport() {
-  const viewport = props.initialViewport ?? latestViewport;
+function restoreEditorViewport(viewport = props.initialViewport ?? latestViewport) {
   if (!view.value || !viewport) return;
   const restoreScroll = () => {
     if (!view.value) return;
diff --git a/packages/app-tests/editorTabSwitchViewportRestore.test.ts b/packages/app-tests/editorTabSwitchViewportRestore.test.ts
index 1261e3c695..ecdfcd03d9 100644
--- a/packages/app-tests/editorTabSwitchViewportRestore.test.ts
+++ b/packages/app-tests/editorTabSwitchViewportRestore.test.ts
@@ -23,7 +23,13 @@ function activateTabDocumentSource(): string {
 
 test("uncached tab activation restores the saved cursor and scroll position", () => {
   const source = activateTabDocumentSource();
-  assert.match(source, /if \(!cached\) \{[\s\S]*?swapEditorDocument\(doc\);[\s\S]*?restoreEditorSelection\(\);[\s\S]*?restoreEditorViewport\(\);[\s\S]*?return;/, "the swapEditorDocument branch must restore selection and viewport before returning");
+  assert.match(source, /if \(!cached\) \{[\s\S]*?swapEditorDocument\(doc\);[\s\S]*?restoreEditorSelection\([^;]*\);[\s\S]*?restoreEditorViewport\([^;]*\);[\s\S]*?return;/, "the swapEditorDocument branch must restore selection and viewport before returning");
+});
+
+test("uncached tabs without saved state do not inherit the previous tab position", () => {
+  const source = activateTabDocumentSource();
+  assert.match(source, /restoreEditorSelection\(props\.initialSelection \?\? \{ anchor: 0, head: 0 \}\);/);
+  assert.match(source, /restoreEditorViewport\(props\.initialViewport \?\? \{ scrollTop: 0, scrollLeft: 0 \}\);/);
 });
 
 test("cached tab activation keeps restoring selection and viewport", () => {
@@ -34,5 +40,5 @@ test("cached tab activation keeps restoring selection and viewport", () => {
 
 test("viewport restore prefers the per-tab saved viewport", () => {
   const source = readFileSync(path.resolve("apps/desktop/src/components/editor/QueryEditor.vue"), "utf8");
-  assert.match(source, /function restoreEditorViewport\(\) \{[\s\S]*?const viewport = props\.initialViewport \?\? latestViewport;/);
+  assert.match(source, /function restoreEditorViewport\(viewport = props\.initialViewport \?\? latestViewport\) \{/);
 });