diff --git a/apps/desktop/src/components/editor/QueryEditor.vue b/apps/desktop/src/components/editor/QueryEditor.vue
index 94ee5664f..f8444c730 100644
--- a/apps/desktop/src/components/editor/QueryEditor.vue
+++ b/apps/desktop/src/components/editor/QueryEditor.vue
@@ -55,10 +55,11 @@ import { createColumnReferencePayload, tableReferenceInsertText } from "@/lib/ed
 import { clearRememberedFocusedQueryEditorView, focusedQueryEditorView, queryEditorInsertContext, registerQueryEditorInsertContext, rememberFocusedQueryEditorView, unregisterQueryEditorInsertContext } from "@/lib/editor/focusedQueryEditorView";
 import { loadObjectMetadataFacet } from "@/lib/metadata/objectMetadataCache";
 import { structurePeekPanelId } from "@/lib/editor/structurePeekPanel";
+import { parkEditorNativeSelection, type EditorNativeSelectionPark } from "@/lib/editor/queryEditorNativeSelection";
 import CodeSnapshotDialog from "@/components/codeSnapshot/CodeSnapshotDialog.vue";
 import QueryEditorContextMenu, { type QueryEditorContextMenuState, type QueryEditorContextMenuActions } from "./QueryEditorContextMenu.vue";
 
-import { readTextFromClipboard } from "@/lib/common/clipboard";
+import { clipboardLineEndings, readTextFromClipboard } from "@/lib/common/clipboard";
 
 import { resolveExecutableSql, type SqlExecutionOverride } from "@/lib/sql/sqlExecutionTarget";
 import { supportsExecutionTargetPicker, type SqlTextRange } from "@/lib/sql/sqlStatementRanges";
@@ -192,6 +193,37 @@ const view = shallowRef<EditorViewType | null>(null);
 const contextMenuOpen = ref(false);
 let contextMenuPointerCleanup: (() => void) | null = null;
 
+// The editor's own context menu is a DOM overlay, so a long selection stays
+// live underneath it and macOS keeps asking the web view to serialize that
+// selection while the pointer moves over the menu. Parking the browser
+// selection for as long as the menu is up is what keeps right click usable on
+// a few hundred selected lines; see queryEditorNativeSelection.ts.
+let parkedNativeSelection: EditorNativeSelectionPark | null = null;
+
+function parkNativeSelectionUnderContextMenu() {
+  const currentView = view.value;
+  if (!currentView) return;
+  parkedNativeSelection?.release();
+  // `clipboardLineEndings` is what the editor registers as its
+  // `clipboardOutputFilter`; passing it here keeps Cmd+C working while the
+  // selection is parked and leaves the copied bytes unchanged.
+  parkedNativeSelection = parkEditorNativeSelection(currentView, { finalizeClipboardText: clipboardLineEndings });
+}
+
+function releaseParkedNativeSelection() {
+  parkedNativeSelection?.release();
+  parkedNativeSelection = null;
+}
+
+watch(
+  contextMenuOpen,
+  (open) => {
+    if (open) parkNativeSelectionUnderContextMenu();
+    else releaseParkedNativeSelection();
+  },
+  { flush: "sync" },
+);
+
 const executionViewportOwnership = createQueryEditorExecutionViewportOwnership();
 
 let contextMenuDoc: Text | null = null;
@@ -2555,6 +2587,7 @@ onBeforeUnmount(() => {
   pointerInteractions.dispose();
   objectNavigation.dispose();
   contextMenuPointerCleanup?.();
+  releaseParkedNativeSelection();
   postCompositionKeyGuardCleanup?.();
   postCompositionKeyGuardCleanup = null;
   batchSelection.dispose();
diff --git a/apps/desktop/src/components/editor/useQueryEditorDiagnostics.ts b/apps/desktop/src/components/editor/useQueryEditorDiagnostics.ts
index 0d32f6198..adab603bb 100644
--- a/apps/desktop/src/components/editor/useQueryEditorDiagnostics.ts
+++ b/apps/desktop/src/components/editor/useQueryEditorDiagnostics.ts
@@ -8,6 +8,7 @@ import type { SqlParameterOptions } from "@/lib/sql/sqlParameters";
 import type { EditorView as EditorViewType } from "@codemirror/view";
 import { type SqlTextRange } from "@/lib/sql/sqlStatementRanges";
 import { executableStatementRangeCacheForDoc, type ExecutableStatementRangeCache } from "@/lib/sql/executableStatementRangeCache";
+import { editorRootSelection } from "@/lib/editor/queryEditorNativeSelection";
 import { buildSqlSemanticModel } from "@/lib/sql/semantic/model";
 import { mergeSqlSemanticReferenceAnalysis } from "@/lib/sql/semantic/references";
 import { sqlServerUseDatabaseBeforeCursor } from "@/lib/sql/sqlCompletionLookupTarget";
@@ -137,15 +138,6 @@ export function useQueryEditorDiagnostics(options: QueryEditorDiagnosticsOptions
       );
   }
 
-  // Mirrors CodeMirror's own root handling: shadow roots only expose
-  // `getSelection` on some browsers, otherwise the owner document holds it.
-  function editorRootSelection(currentView: EditorViewType): Selection | null {
-    const root = currentView.root as unknown as ShadowRoot & { getSelection?: () => Selection | null };
-    if (root.nodeType !== 11) return (root as unknown as Document).getSelection();
-    if (typeof root.getSelection === "function") return root.getSelection() ?? null;
-    return root.ownerDocument?.getSelection() ?? null;
-  }
-
   // See queryEditorDiagnosticCaretAnchor.ts for why the browser caret needs re-anchoring.
   function reanchorCaretAfterDiagnostics(currentView: EditorViewType) {
     const selection = currentView.state.selection;
diff --git a/apps/desktop/src/lib/__tests__/editorThemes.spec.ts b/apps/desktop/src/lib/__tests__/editorThemes.spec.ts
index 572fc2075..dc8c82ad7 100644
--- a/apps/desktop/src/lib/__tests__/editorThemes.spec.ts
+++ b/apps/desktop/src/lib/__tests__/editorThemes.spec.ts
@@ -222,6 +222,20 @@ describe("SQL builtin highlight tag", () => {
 });
 
 describe("editor gutters", () => {
+  it("does not let the gutter minimum height cycle against the scroller content height", () => {
+    const rules = buildEditorFontThemeRules();
+
+    // CodeMirror's base theme applies `min-height: 100%` to `.cm-gutter` while
+    // `.cm-gutters` is sized from the scroller content (`.cm-content`), so the
+    // percentage resolves against a height the gutter itself participates in.
+    // WebKit then re-runs layout for the whole gutter subtree whenever layout
+    // is forced, which macOS 27 does on every selection collapse: a 639 line
+    // query made right click / Esc / select-all freeze for ~180ms. The gutter
+    // spacers already span the full content height and `.cm-gutters` paints the
+    // background, so the cyclic minimum must stay at 0.
+    expect(rules[".cm-gutter"]).toMatchObject({ minHeight: "0" });
+  });
+
   it("keeps single line numbers vertically centered in the base rule", () => {
     const rules = buildEditorFontThemeRules();
 
diff --git a/apps/desktop/src/lib/editor/__tests__/queryEditorNativeSelection.spec.ts b/apps/desktop/src/lib/editor/__tests__/queryEditorNativeSelection.spec.ts
new file mode 100644
index 000000000..3d701f6d8
--- /dev/null
+++ b/apps/desktop/src/lib/editor/__tests__/queryEditorNativeSelection.spec.ts
@@ -0,0 +1,120 @@
+// @vitest-environment happy-dom
+import { describe, expect, it, vi } from "vitest";
+import type { EditorView } from "@codemirror/view";
+import { NATIVE_SELECTION_PARK_MIN_CHARS, parkEditorNativeSelection } from "../queryEditorNativeSelection";
+
+const DOC = `SELECT ${"x".repeat(NATIVE_SELECTION_PARK_MIN_CHARS)}`;
+
+interface FakeView {
+  view: EditorView;
+  contentDOM: HTMLElement;
+  dispatch: ReturnType<typeof vi.fn>;
+  selectedText: () => string;
+}
+
+function fakeView(from: number, to: number): FakeView {
+  const dom = document.createElement("div");
+  const contentDOM = document.createElement("div");
+  const paragraph = document.createElement("p");
+  const text = document.createTextNode(DOC);
+  paragraph.appendChild(text);
+  contentDOM.appendChild(paragraph);
+  dom.appendChild(contentDOM);
+  document.body.appendChild(dom);
+
+  const range = { from, to, empty: from === to, head: to, anchor: from };
+  const dispatch = vi.fn();
+  const state = {
+    selection: { main: range, ranges: [range] },
+    lineBreak: "\n",
+    readOnly: false,
+    sliceDoc: (start: number, end: number) => DOC.slice(start, end),
+  };
+  const view = {
+    root: document,
+    dom,
+    contentDOM,
+    state,
+    dispatch,
+    domAtPos: (pos: number) => ({ node: text, offset: Math.min(pos, DOC.length) }),
+  } as unknown as EditorView;
+
+  const selection = document.getSelection()!;
+  selection.collapse(text, from);
+  selection.extend(text, to);
+
+  return { view, contentDOM, dispatch, selectedText: () => document.getSelection()?.toString() ?? "" };
+}
+
+function copyEvent(target: EventTarget, type = "copy") {
+  const data = { clearData: vi.fn(), setData: vi.fn() };
+  const event = new Event(type, { bubbles: true, cancelable: true });
+  Object.defineProperty(event, "clipboardData", { value: data });
+  target.dispatchEvent(event);
+  return { data, event };
+}
+
+describe("parkEditorNativeSelection", () => {
+  it("leaves short selections alone", () => {
+    const { view } = fakeView(0, 5);
+    expect(parkEditorNativeSelection(view)).toBeNull();
+    expect(document.getSelection()?.toString()).toBe(DOC.slice(0, 5));
+  });
+
+  it("parks the browser selection outside the content element while the state keeps its selection", () => {
+    const { view, contentDOM } = fakeView(10, 10 + NATIVE_SELECTION_PARK_MIN_CHARS);
+    const park = parkEditorNativeSelection(view);
+
+    expect(park).not.toBeNull();
+    const selection = document.getSelection()!;
+    expect(contentDOM.contains(selection.anchorNode)).toBe(false);
+    expect(view.state.selection.main.to - view.state.selection.main.from).toBe(NATIVE_SELECTION_PARK_MIN_CHARS);
+
+    park!.release();
+    expect(contentDOM.contains(document.getSelection()?.anchorNode ?? null)).toBe(true);
+  });
+
+  it("fills the clipboard for a copy CodeMirror declined, using the injected normalizer", () => {
+    const { view, contentDOM } = fakeView(0, NATIVE_SELECTION_PARK_MIN_CHARS);
+    const finalize = vi.fn((text: string) => text.replace(/\n/g, "\r\n"));
+    const park = parkEditorNativeSelection(view, { finalizeClipboardText: finalize });
+
+    const { data, event } = copyEvent(contentDOM);
+    expect(finalize).toHaveBeenCalledWith(DOC.slice(0, NATIVE_SELECTION_PARK_MIN_CHARS));
+    expect(data.setData).toHaveBeenCalledWith("text/plain", DOC.slice(0, NATIVE_SELECTION_PARK_MIN_CHARS).replace(/\n/g, "\r\n"));
+    expect(event.defaultPrevented).toBe(true);
+
+    park!.release();
+  });
+
+  it("cuts through its own path when CodeMirror declines", () => {
+    const { view, contentDOM, dispatch } = fakeView(0, NATIVE_SELECTION_PARK_MIN_CHARS);
+    const park = parkEditorNativeSelection(view);
+
+    const { data } = copyEvent(contentDOM, "cut");
+    expect(data.setData).toHaveBeenCalled();
+    expect(dispatch).toHaveBeenCalledWith(expect.objectContaining({ changes: [{ from: 0, to: NATIVE_SELECTION_PARK_MIN_CHARS }], userEvent: "delete.cut" }));
+
+    park!.release();
+  });
+
+  it("stays out of the way when the editor already handled the copy", () => {
+    const { view, contentDOM } = fakeView(0, NATIVE_SELECTION_PARK_MIN_CHARS);
+    const park = parkEditorNativeSelection(view);
+    contentDOM.addEventListener("copy", (event) => event.preventDefault());
+
+    const { data } = copyEvent(contentDOM);
+    expect(data.setData).not.toHaveBeenCalled();
+
+    park!.release();
+  });
+
+  it("stops listening once released", () => {
+    const { view, contentDOM } = fakeView(0, NATIVE_SELECTION_PARK_MIN_CHARS);
+    const park = parkEditorNativeSelection(view)!;
+    park.release();
+
+    const { data } = copyEvent(contentDOM);
+    expect(data.setData).not.toHaveBeenCalled();
+  });
+});
diff --git a/apps/desktop/src/lib/editor/editorThemes.ts b/apps/desktop/src/lib/editor/editorThemes.ts
index c928f5e33..98a47fb98 100644
--- a/apps/desktop/src/lib/editor/editorThemes.ts
+++ b/apps/desktop/src/lib/editor/editorThemes.ts
@@ -824,6 +824,16 @@ export function buildEditorFontThemeRules(opts?: { fixedHeight?: boolean; scroll
     ".cm-trimmedSelection-bottomRight": {
       borderBottomRightRadius: "3px",
     },
+    // CodeMirror's base theme gives `.cm-gutter` `min-height: 100%` inside a
+    // `.cm-gutters` box that is itself sized by `height: 100%` of a scroller
+    // whose height comes from the content. That percentage cycle makes WebKit
+    // re-run layout for the whole gutter subtree on every layout pass, which
+    // costs ~160ms per collapse with a few hundred lines selected. The gutter's
+    // own spacers already span the full content height and the background is
+    // painted by `.cm-gutters`, so dropping the cyclic minimum is visually inert.
+    ".cm-gutter": {
+      minHeight: "0",
+    },
     ".cm-gutters": {
       borderRight: "0 !important",
       fontSize: `var(${EDITOR_FONT_SIZE_CSS_VAR}, ${defaults?.size ?? 13}px)`,
diff --git a/apps/desktop/src/lib/editor/queryEditorNativeSelection.ts b/apps/desktop/src/lib/editor/queryEditorNativeSelection.ts
new file mode 100644
index 000000000..e58a4e9a1
--- /dev/null
+++ b/apps/desktop/src/lib/editor/queryEditorNativeSelection.ts
@@ -0,0 +1,188 @@
+import type { EditorView } from "@codemirror/view";
+import { appendDebugLog } from "@/lib/backend/debugLog";
+
+/**
+ * macOS 26/27 asks the web view to serialize the browser selection into an
+ * attributed string whenever the pointer dwells over text services (the
+ * Writing Tools check that follows a text selection). Resolving that string
+ * means a colour lookup per styled run, so one request over a few hundred
+ * highlighted lines of SQL costs well over 100 ms of web process main thread
+ * time — and while one of the app's own menus sits on top of the selection
+ * every pointer move over that menu asks again, which saturates the main
+ * thread and makes right click, Esc and the whole window feel frozen.
+ *
+ * The browser selection does not have to cover the selection for the editor to
+ * behave: CodeMirror paints the selection itself (`drawSelection` keeps the
+ * native one transparent), it copies from its own state, and it ignores a
+ * selection parked outside its content element. So while an overlay menu is
+ * shown on top of the editor the browser selection is parked on the editor
+ * chrome and restored as soon as the menu closes.
+ *
+ * Parking outside `contentDOM` is what makes CodeMirror leave the editor state
+ * alone (it maps a foreign selection back to the selection it already has), so
+ * the parked selection stays where it is, but it also means CodeMirror's own
+ * `copy`/`cut` handler declines the event — see `handleParkedClipboardEvent`,
+ * which supplies the clipboard text in that window.
+ */
+
+/**
+ * Selections shorter than this are serialized cheaply enough that parking them
+ * would only trade a measurable cost for an invisible one.
+ */
+export const NATIVE_SELECTION_PARK_MIN_CHARS = 1000;
+
+export interface EditorNativeSelectionPark {
+  /** Put the browser selection back where the editor state has it. */
+  release(): void;
+}
+
+export interface EditorNativeSelectionParkOptions {
+  /**
+   * Applied to the text the parked copy path puts on the clipboard. Pass the
+   * same normalizer the editor registers as `EditorView.clipboardOutputFilter`
+   * (DBX rewrites line endings there) so copying with the menu open matches
+   * copying with it closed. Injected rather than read from the facet so this
+   * module never pulls CodeMirror into the startup bundle.
+   */
+  finalizeClipboardText?: (text: string) => string;
+}
+
+/**
+ * Mirrors CodeMirror's own root handling: shadow roots only expose
+ * `getSelection` on some browsers, otherwise the owner document holds it.
+ */
+export function editorRootSelection(currentView: EditorView): Selection | null {
+  const root = currentView.root as unknown as ShadowRoot & { getSelection?: () => Selection | null };
+  if (root.nodeType !== 11) return (root as unknown as Document).getSelection();
+  if (typeof root.getSelection === "function") return root.getSelection() ?? null;
+  return root.ownerDocument?.getSelection() ?? null;
+}
+
+function isParkedOutsideContent(currentView: EditorView, selection: Selection): boolean {
+  const anchor = selection.anchorNode;
+  return !!anchor && !currentView.contentDOM.contains(anchor);
+}
+
+function parkSelection(currentView: EditorView, selection: Selection): void {
+  try {
+    // `view.dom` (the editor element) sits outside `view.contentDOM`, so
+    // CodeMirror treats the parked selection as somebody else's and leaves the
+    // editor state alone. It is also far from the highlighted text, which is
+    // what keeps the attributed string cheap.
+    selection.collapse(currentView.dom, 0);
+  } catch {
+    // WebKit rejects a collapse whose node disappeared between layout passes.
+  }
+}
+
+function restoreSelectionFromState(currentView: EditorView, selection: Selection): void {
+  try {
+    const main = currentView.state.selection.main;
+    const anchor = currentView.domAtPos(main.from);
+    const head = main.empty ? anchor : currentView.domAtPos(main.to);
+    selection.collapse(anchor.node, anchor.offset);
+    if (!main.empty) selection.extend(head.node, head.offset);
+  } catch {
+    // WebKit refuses `extend` when the target moved in the meantime; the next
+    // selection change makes CodeMirror rewrite the browser selection anyway.
+  }
+}
+
+/**
+ * The text CodeMirror would put on the clipboard for the current state.
+ *
+ * Mirrors CodeMirror's `copiedRange` (join the non-empty ranges with the
+ * document line break, then run the app's output filter) so a copy taken while
+ * the selection is parked is byte-identical to a copy taken while it is not.
+ */
+function copiedEditorText(currentView: EditorView, finalizeText: (text: string) => string): { text: string; ranges: { from: number; to: number }[] } | null {
+  const { state } = currentView;
+  const parts: string[] = [];
+  const ranges: { from: number; to: number }[] = [];
+  for (const range of state.selection.ranges) {
+    if (range.empty) continue;
+    parts.push(state.sliceDoc(range.from, range.to));
+    ranges.push({ from: range.from, to: range.to });
+  }
+  if (!parts.length) return null;
+  return { text: finalizeText(parts.join(state.lineBreak)), ranges };
+}
+
+/**
+ * Fills the clipboard for a `copy`/`cut` that CodeMirror declined.
+ *
+ * CodeMirror's handler only acts when the browser selection sits inside
+ * `contentDOM` (`handlers.copy` bails out on `hasSelection(view.contentDOM,
+ * …)`), which a parked selection deliberately is not. Without this the user
+ * would copy the parked caret instead of the visible selection.
+ *
+ * The app's own menus close on the first non-modifier keydown, so a Cmd+C
+ * normally releases the park before the copy lands and never reaches here;
+ * this covers the copies that arrive while the selection is still parked
+ * (clicking a copy item, platform-initiated copies).
+ */
+function handleParkedClipboardEvent(currentView: EditorView, finalizeClipboardText: (text: string) => string, released: () => boolean, event: ClipboardEvent): void {
+  if (released() || event.defaultPrevented) return;
+  // `copy`/`cut` fire on the focused element; a parked selection only exists
+  // while the editor owns the interaction, so anything else is somebody else's.
+  const target = event.target as Node | null;
+  if (target && !currentView.dom.contains(target)) return;
+  const payload = copiedEditorText(currentView, finalizeClipboardText);
+  if (!payload) return;
+  const data = event.clipboardData;
+  if (!data) return;
+  data.clearData();
+  data.setData("text/plain", payload.text);
+  if (event.type === "cut" && !currentView.state.readOnly) currentView.dispatch({ changes: payload.ranges, scrollIntoView: true, userEvent: "delete.cut" });
+  event.preventDefault();
+}
+
+/**
+ * Parks the browser selection while an overlay menu covers the editor.
+ *
+ * @returns a handle that restores the browser selection, or `null` when there
+ * was nothing worth parking.
+ */
+export function parkEditorNativeSelection(currentView: EditorView, options: EditorNativeSelectionParkOptions = {}): EditorNativeSelectionPark | null {
+  const main = currentView.state.selection.main;
+  if (main.empty || main.to - main.from < NATIVE_SELECTION_PARK_MIN_CHARS) return null;
+  const selection = editorRootSelection(currentView);
+  if (!selection || !selection.anchorNode || !currentView.dom.contains(selection.anchorNode)) return null;
+  // Kept for field diagnosis: it only writes while debug logging is switched
+  // on, and it is the one line that shows whether the parked window was even
+  // entered when somebody reports the editor still stuttering.
+  appendDebugLog("info", "[DBX][QueryEditor:native-selection:park]", { chars: main.to - main.from });
+
+  parkSelection(currentView, selection);
+  let released = false;
+  let frame = 0;
+  const finalizeClipboardText = options.finalizeClipboardText ?? ((text: string) => text);
+  // `copy`/`cut` bubble through the document, so listening there catches the
+  // event no matter which editor chrome inside the view holds focus.
+  const doc = currentView.dom.ownerDocument;
+  const win = doc.defaultView ?? window;
+  const onCopy = (event: ClipboardEvent) => handleParkedClipboardEvent(currentView, finalizeClipboardText, () => released, event);
+  doc.addEventListener("copy", onCopy);
+  doc.addEventListener("cut", onCopy);
+  // CodeMirror rewrites the browser selection from its own state on every
+  // selection update (menu actions, diagnostics re-anchoring, typing), so a
+  // single collapse does not stick. Reading `anchorNode` costs no layout.
+  const keepParked = () => {
+    if (released) return;
+    if (!isParkedOutsideContent(currentView, selection)) parkSelection(currentView, selection);
+    frame = win.requestAnimationFrame(keepParked);
+  };
+  frame = win.requestAnimationFrame(keepParked);
+
+  return {
+    release() {
+      if (released) return;
+      released = true;
+      doc.removeEventListener("copy", onCopy);
+      doc.removeEventListener("cut", onCopy);
+      win.cancelAnimationFrame(frame);
+      const live = editorRootSelection(currentView);
+      if (live && isParkedOutsideContent(currentView, live)) restoreSelectionFromState(currentView, live);
+    },
+  };
+}