diff --git a/packages/app/src/assistant-file-links/parse.ts b/packages/app/src/assistant-file-links/parse.ts
index bd0015f0b..092f3b4dc 100644
--- a/packages/app/src/assistant-file-links/parse.ts
+++ b/packages/app/src/assistant-file-links/parse.ts
@@ -140,6 +140,7 @@ function parseLineFragment(value: string): Pick<InlinePathTarget, "lineStart" |
  *
  * Supported:
  * - `filename:linenumber`
+ * - `filename:linenumber:columnnumber` as a line target
  * - `filename:lineStart-lineEnd`
  *
  * Not supported (by design):
diff --git a/packages/app/src/components/markdown/html-ish.test.ts b/packages/app/src/components/markdown/html-ish.test.ts
index ac6f2ad8b..c47a718fe 100644
--- a/packages/app/src/components/markdown/html-ish.test.ts
+++ b/packages/app/src/components/markdown/html-ish.test.ts
@@ -256,6 +256,12 @@ describe("splitHtmlishMarkdown", () => {
     expect(splitHtmlishMarkdown(source)).toEqual([{ kind: "markdown", text: source }]);
   });
 
+  it("terminates when an unmatched backtick follows a closed inline code span", () => {
+    const source = "Use `<details><summary>Example</summary>Body</details>` before `dangling";
+
+    expect(splitHtmlishMarkdown(source)).toEqual([{ kind: "markdown", text: source }]);
+  });
+
   it("still parses normal details outside code", () => {
     expect(splitHtmlishMarkdown("`code`\n<details><summary>Real</summary>Body</details>")).toEqual([
       { kind: "markdown", text: "`code`\n" },
diff --git a/packages/app/src/components/markdown/html-ish.ts b/packages/app/src/components/markdown/html-ish.ts
index b68e734b5..7a92f0d20 100644
--- a/packages/app/src/components/markdown/html-ish.ts
+++ b/packages/app/src/components/markdown/html-ish.ts
@@ -651,8 +651,13 @@ function getInlineCodeRanges(
     }
 
     const marker = open[0];
-    const close = findClosingBacktickRun(source, BACKTICK_RUN_RE.lastIndex, marker, fencedRanges);
+    const afterOpen = BACKTICK_RUN_RE.lastIndex;
+    const close = findClosingBacktickRun(source, afterOpen, marker, fencedRanges);
     if (!close) {
+      // Unmatched backtick run — skip past it so the loop doesn't restart from 0.
+      // findClosingBacktickRun exhausts the global regex, which resets lastIndex
+      // to 0 when exec() returns null (ECMAScript §22.2.7.2).
+      BACKTICK_RUN_RE.lastIndex = afterOpen;
       continue;
     }
 
diff --git a/packages/app/src/hooks/use-keyboard-shortcuts.ts b/packages/app/src/hooks/use-keyboard-shortcuts.ts
index ae0671c25..eb58f3ba6 100644
--- a/packages/app/src/hooks/use-keyboard-shortcuts.ts
+++ b/packages/app/src/hooks/use-keyboard-shortcuts.ts
@@ -9,6 +9,7 @@ import {
   type ChordState,
   resolveKeyboardShortcut,
   buildEffectiveBindings,
+  getWorkspaceIndexJumpModifierKey,
 } from "@/keyboard/keyboard-shortcuts";
 import { resolveKeyboardFocusScope } from "@/keyboard/focus-scope";
 import {
@@ -73,6 +74,20 @@ export function useKeyboardShortcuts({
     const isDesktopApp = getIsElectronRuntime();
     const isMac = getShortcutOs() === "mac";
 
+    // Only the modifier that actually performs the workspace-index jump on this
+    // runtime should reveal the sidebar number badges (Alt on web, Cmd on
+    // desktop Mac, Ctrl on desktop non-Mac). The store ORs altDown/cmdOrCtrlDown
+    // to drive badge visibility, so we set the flag matching this runtime.
+    const badgeModifierKey = getWorkspaceIndexJumpModifierKey({ isMac, isDesktop: isDesktopApp });
+    const setBadgeModifierDown = (down: boolean) => {
+      const state = useKeyboardShortcutsStore.getState();
+      if (isDesktopApp) {
+        state.setCmdOrCtrlDown(down);
+      } else {
+        state.setAltDown(down);
+      }
+    };
+
     const shouldHandle = () => {
       if (typeof document === "undefined") return false;
       if (document.visibilityState !== "visible") return false;
@@ -156,11 +171,8 @@ export function useKeyboardShortcuts({
       }
 
       const key = event.key ?? "";
-      if (key === "Alt" && !event.shiftKey) {
-        useKeyboardShortcutsStore.getState().setAltDown(true);
-      }
-      if (isDesktopApp && (key === "Meta" || key === "Control") && !event.shiftKey) {
-        useKeyboardShortcutsStore.getState().setCmdOrCtrlDown(true);
+      if (key === badgeModifierKey && !event.shiftKey) {
+        setBadgeModifierDown(true);
       }
       if (key === "Shift") {
         const state = useKeyboardShortcutsStore.getState();
@@ -231,11 +243,8 @@ export function useKeyboardShortcuts({
 
     const handleKeyUp = (event: KeyboardEvent) => {
       const key = event.key ?? "";
-      if (key === "Alt") {
-        useKeyboardShortcutsStore.getState().setAltDown(false);
-      }
-      if (isDesktopApp && (key === "Meta" || key === "Control")) {
-        useKeyboardShortcutsStore.getState().setCmdOrCtrlDown(false);
+      if (key === badgeModifierKey) {
+        setBadgeModifierDown(false);
       }
     };
 
diff --git a/packages/app/src/keyboard/keyboard-shortcuts.test.ts b/packages/app/src/keyboard/keyboard-shortcuts.test.ts
index a797aea9b..bec812563 100644
--- a/packages/app/src/keyboard/keyboard-shortcuts.test.ts
+++ b/packages/app/src/keyboard/keyboard-shortcuts.test.ts
@@ -3,6 +3,7 @@ import {
   buildKeyboardShortcutHelpSections,
   buildEffectiveBindings,
   getBindingIdForAction,
+  getWorkspaceIndexJumpModifierKey,
   resolveKeyboardShortcut,
   type ChordState,
   type KeyboardShortcutContext,
@@ -638,3 +639,18 @@ describe("keyboard-shortcut help sections", () => {
     ).toBeNull();
   });
 });
+
+describe("getWorkspaceIndexJumpModifierKey", () => {
+  it("uses Alt on web, regardless of OS", () => {
+    expect(getWorkspaceIndexJumpModifierKey({ isMac: true, isDesktop: false })).toBe("Alt");
+    expect(getWorkspaceIndexJumpModifierKey({ isMac: false, isDesktop: false })).toBe("Alt");
+  });
+
+  it("uses Cmd (Meta) on desktop Mac, not Control or Alt", () => {
+    expect(getWorkspaceIndexJumpModifierKey({ isMac: true, isDesktop: true })).toBe("Meta");
+  });
+
+  it("uses Ctrl on desktop non-Mac, not Meta or Alt", () => {
+    expect(getWorkspaceIndexJumpModifierKey({ isMac: false, isDesktop: true })).toBe("Control");
+  });
+});
diff --git a/packages/app/src/keyboard/keyboard-shortcuts.ts b/packages/app/src/keyboard/keyboard-shortcuts.ts
index d3fbbd088..40358977d 100644
--- a/packages/app/src/keyboard/keyboard-shortcuts.ts
+++ b/packages/app/src/keyboard/keyboard-shortcuts.ts
@@ -1344,6 +1344,21 @@ export function getDefaultKeysForAction(
   return null;
 }
 
+/**
+ * The `KeyboardEvent.key` whose hold reveals the sidebar workspace-jump number
+ * badges. It must match the modifier of the active `workspace.navigate.index`
+ * binding for this runtime, otherwise the badges appear for a modifier that
+ * does not actually jump: Alt on web, Cmd (Meta) on desktop Mac, Ctrl on
+ * desktop non-Mac.
+ */
+export function getWorkspaceIndexJumpModifierKey(platform: {
+  isMac: boolean;
+  isDesktop: boolean;
+}): "Alt" | "Meta" | "Control" {
+  if (!platform.isDesktop) return "Alt";
+  return platform.isMac ? "Meta" : "Control";
+}
+
 export function buildKeyboardShortcutHelpSections(
   input: KeyboardShortcutPlatformContext,
   bindings: readonly ParsedShortcutBinding[] = DEFAULT_BINDINGS,