From 397855c9aba6f4de2f7a4d0d5d70b4379fdb3139 Mon Sep 17 00:00:00 2001
From: npub1mprnacetjua2xx3p5eddmhxyk6wv929ymm5py8kd2xfxurxahspqqlgyta
 <d8473ee32b973aa31a21a65adddcc4b69cc2a8a4dee8121ecd51926e0cddbc02@buzz.block.builderlab.xyz>
Date: Sun, 2 Aug 2026 20:05:40 -0400
Subject: [PATCH] fix(desktop): scope wheel exemption to active terminal

Co-authored-by: npub1mprnacetjua2xx3p5eddmhxyk6wv929ymm5py8kd2xfxurxahspqqlgyta <d8473ee32b973aa31a21a65adddcc4b69cc2a8a4dee8121ecd51926e0cddbc02@buzz.block.builderlab.xyz>
Signed-off-by: npub1mprnacetjua2xx3p5eddmhxyk6wv929ymm5py8kd2xfxurxahspqqlgyta <d8473ee32b973aa31a21a65adddcc4b69cc2a8a4dee8121ecd51926e0cddbc02@buzz.block.builderlab.xyz>
---
 .../hooks/useWebviewScrollBoundaryLock.ts     |  2 +-
 desktop/tests/e2e/overscroll-boundary.spec.ts | 33 ++++++++++++++++---
 2 files changed, 30 insertions(+), 5 deletions(-)

diff --git a/desktop/src/shared/hooks/useWebviewScrollBoundaryLock.ts b/desktop/src/shared/hooks/useWebviewScrollBoundaryLock.ts
index 88717b9ea..50d132ec0 100644
--- a/desktop/src/shared/hooks/useWebviewScrollBoundaryLock.ts
+++ b/desktop/src/shared/hooks/useWebviewScrollBoundaryLock.ts
@@ -2,7 +2,7 @@ import * as React from "react";
 
 const BOUNDARY_EPSILON_PX = 1;
 const CONVERSATION_SCROLL_SELECTOR = "[data-buzz-conversation-scroll]";
-const TERMINAL_SUBSTRATE_SELECTOR = "[data-terminal-owner]";
+const TERMINAL_SUBSTRATE_SELECTOR = '[data-terminal-owner="terminal"]';
 const SCROLLABLE_OVERFLOW_VALUES = new Set(["auto", "scroll", "overlay"]);
 
 function isHTMLElement(value: EventTarget | null): value is HTMLElement {
diff --git a/desktop/tests/e2e/overscroll-boundary.spec.ts b/desktop/tests/e2e/overscroll-boundary.spec.ts
index 64a931e60..e7e561c12 100644
--- a/desktop/tests/e2e/overscroll-boundary.spec.ts
+++ b/desktop/tests/e2e/overscroll-boundary.spec.ts
@@ -70,7 +70,7 @@ test("locks viewport rubber-band outside conversation scrollers", async ({
   // gesture alone so the substrate's own handler can receive it.
   await page.evaluate(() => {
     const terminal = document.createElement("section");
-    terminal.dataset.terminalOwner = "buzz";
+    terminal.dataset.terminalOwner = "terminal";
     terminal.dataset.testid = "terminal-wheel-target";
     document.body.append(terminal);
   });
@@ -112,18 +112,43 @@ test("locks horizontal viewport pan everywhere", async ({ page }) => {
 
   await page.evaluate(() => {
     const terminal = document.createElement("section");
-    terminal.dataset.terminalOwner = "buzz";
+    terminal.dataset.terminalOwner = "terminal";
     terminal.dataset.testid = "terminal-wheel-target";
     document.body.append(terminal);
   });
-  for (const deltaX of [-120, 120]) {
+  for (const [deltaX, deltaY, prevented] of [
+    [120, 0, true],
+    [0, 120, false],
+    [120, 120, false],
+    [120, 20, true],
+  ] as const) {
     await expect(
       dispatchWheelPrevented(page, '[data-testid="terminal-wheel-target"]', {
         deltaX,
+        deltaY,
       }),
-    ).resolves.toBe(true);
+    ).resolves.toBe(prevented);
   }
 
+  // A concealed substrate is not an active custom wheel consumer. Keep dead
+  // space locked even if a future layout places Buzz content inside it.
+  await page.evaluate(() => {
+    const terminal = document.querySelector<HTMLElement>(
+      '[data-testid="terminal-wheel-target"]',
+    );
+    const buzzContent = document.createElement("div");
+    buzzContent.dataset.testid = "concealed-terminal-dead-space";
+    terminal?.append(buzzContent);
+    if (terminal) terminal.dataset.terminalOwner = "buzz";
+  });
+  await expect(
+    dispatchWheelPrevented(
+      page,
+      '[data-testid="concealed-terminal-dead-space"]',
+      { deltaY: 120 },
+    ),
+  ).resolves.toBe(true);
+
   // A predominantly vertical gesture with slight horizontal drift still
   // reaches the conversation scroller.
   await expect(