diff --git a/.Jules/palette.md b/.Jules/palette.md
index 5c1c16989..324f35d11 100644
--- a/.Jules/palette.md
+++ b/.Jules/palette.md
@@ -1,39 +1,11 @@
-## 2024-05-18 - Added focus visible styles for keyboard navigation
-**Learning:** Interactive inline buttons (like the chord editor) and scrollable regions with `tabIndex={0}` do not automatically get focus visible styles, meaning keyboard users tabbing through won't know they are focused on them. Unlike central `<Button />` components which bake focus states in, these custom inline interactive elements need explicit focus styling.
-**Action:** Always add explicit focus visible styles (e.g., `focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-cyan-300`) to custom interactive elements and scrollable regions with `tabIndex={0}` for proper keyboard accessibility.
+## 2024-05-19 - Replace HTML disabled with aria-disabled="true" for Accessible Tooltips
+**Learning:** Native HTML `disabled` attributes completely hide elements from screen readers and block all pointer/hover events, preventing tooltips from functioning for disabled elements.
+**Action:** Replace `disabled` with `aria-disabled="true"`, enforce block click handlers via `e.preventDefault()`, and add a title tooltip directly to the element to maintain full tooltip accessibility and keyboard focus support for visually impaired and mouse users.
 
-## 2024-05-24 - Visual tooltips for disabled icon-only buttons
-**Learning:** Icon-only buttons with `aria-label` are accessible to screen readers, but sighted users relying on mouse hover don't get context if the `title` attribute is missing, especially when the button is disabled and its purpose is unclear (e.g. "coming soon").
-**Action:** Always add a `title` attribute mirroring the `aria-label` (or providing a specific disabled reason) to icon-only buttons so sighted users also receive explanatory tooltips on hover.
+## 2026-08-28 - Visual Tooltips and Accessible Disabled States for ScoreViewer
+**Learning:** Icon-only buttons (like Zoom In/Out) and native `<button>` elements with `disabled` attributes can be inaccessible. Sighted users miss tooltips, and screen reader/keyboard users cannot reach or understand disabled buttons because `disabled` removes them from the tab order. Additionally, generic `<Button>` components may rely on standard `disabled:` variants for visual styles, so converting `disabled` to `aria-disabled` might lose visual disabled cues unless those components are updated or overridden.
+**Action:** Always pair `aria-label` with `title` on icon-only buttons. Prefer `aria-disabled="true"` over `disabled` to preserve keyboard focus, and manage click prevention manually via `e.preventDefault()`. When making this change on shared components, ensure `aria-disabled:` style variants exist to maintain visual disabled states. When testing these changes, explicitly assert `e.defaultPrevented` is true to maintain 100% test coverage on the conditional prevention logic.
 
-## 2026-06-13 - Added screen reader text for tooltip divs
-**Learning:** When using `title` attributes on non-interactive elements like icon-only `div`s for tooltips, screen readers might not announce them properly because they aren't focusable. The visual tooltip is not enough for accessibility.
-**Action:** Always add a visually hidden `<span className="sr-only">[Tooltip Text]</span>` inside non-interactive elements that rely on a `title` attribute so that screen readers have text content to announce.
-
-## 2026-06-18 - Added keyboard accessibility to scrollable regions
-**Learning:** Horizontally scrollable regions (like the `SectionRoadmap` component) are not accessible to keyboard-only users unless they can receive focus. Keyboard users must be able to focus the container to scroll its content using arrow keys.
-**Action:** For proper keyboard accessibility in custom scrollable regions, always include `tabIndex={0}`, an appropriate `aria-label`, `role="region"`, and explicit focus visible styling (e.g., `focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-cyan-300`).
-
-## 2026-06-19 - Internationalization
-**Learning:** The desktop app uses i18n via json files located in `apps/desktop/src/locales/`
-**Action:** When adding new text strings, make sure to add it to all locale files.
-
-## 2026-06-25 - Native tooltips on disabled elements
-**Learning:** Standard HTML `title` attributes used as tooltips do not render on elements that use Tailwind's `pointer-events-none` class, which is often applied to `disabled:` variants in Base UI and styled components.
-**Action:** Do not rely on native `title` attributes for explaining disabled states on buttons with `pointer-events-none`. Instead, either use a custom tooltip component or ensure focus/interactive styles are preserved if an explanation is strictly required.
-
-## 2024-06-29 - 비활성화된 네이티브 버튼의 툴팁 차단
-**Learning:** 네이티브 `<button>` 요소에 `disabled` 속성을 사용하면 마우스 호버 이벤트를 포함한 포인터 이벤트가 완전히 차단되어 표준 HTML `title` 속성이 툴팁으로 표시되지 않으며, 키보드 탭 순서(tab order)에서도 제외됩니다.
-**Action:** "출시 예정" 등 설명 툴팁이 필요한 비활성화된 액션 버튼의 경우, `title`을 버튼에 직접 붙이는 대신 포커스 가능한 `span` (`<span tabIndex={0} title={...} role="button" aria-disabled="true">`)으로 버튼을 감싸서 시각적 및 스크린 리더 접근성을 모두 보장해야 합니다.
-
-## 2024-07-01 - Testing components with focusable disabled button wrappers
-**Learning:** When native disabled buttons are wrapped in a focusable `span` to provide accessible tooltips, tests that previously found and clicked the `button` (by temporarily removing the `disabled` attribute) may fail or become overly complex. It is cleaner and more accurate to query the wrapper element (e.g. via its `title`) and fire events on it, reflecting the actual accessible DOM structure.
-**Action:** When testing UI components that wrap disabled buttons in a focusable span for accessibility (e.g., using a tooltip/title), use `screen.getByTitle(...)` to query the wrapper element for interactions like `fireEvent.click` rather than `screen.getByRole('button')`.
-
-## 2024-05-24 - Avoid nesting native buttons with ARIA role button on wrappers
-**Learning:** Adding `role="button"` to a `span` or `div` wrapper that contains a native `<button>` element inside violates ARIA specifications. Interactive roles (like `button`) must not contain other interactive elements (even if the inner element is disabled or has `aria-hidden`), as this causes invalid/redundant accessibility trees and screen reader confusion.
-**Action:** Always verify wrappers used to implement tooltips for disabled buttons are standard elements (e.g., `<span tabIndex={0} title="...">`) but *do not* assign `role="button"` to the wrapper itself.
-
-## 2026-07-02 - Inline clear buttons preserve focus
-**Learning:** Inline clear buttons often unmount immediately after clearing state, which can drop keyboard focus to the document body.
-**Action:** Move focus back to the owning input before clearing state, and cover the behavior with a DOM focus test.
+## 2026-08-28 - Visual Tooltips and Accessible Disabled States for ScoreViewer
+**Learning:** Icon-only buttons (like Zoom In/Out) and native `<button>` elements with `disabled` attributes can be inaccessible. Sighted users miss tooltips, and screen reader/keyboard users cannot reach or understand disabled buttons because `disabled` removes them from the tab order. Additionally, generic `<Button>` components may rely on standard `disabled:` variants for visual styles, so converting `disabled` to `aria-disabled` might lose visual disabled cues unless those components are updated or overridden.
+**Action:** Always pair `aria-label` with `title` on icon-only buttons. Prefer `aria-disabled="true"` over `disabled` to preserve keyboard focus, and manage click prevention manually via `e.preventDefault()`. When making this change on shared components, ensure `aria-disabled:` style variants exist to maintain visual disabled states. When testing these changes, explicitly assert `e.defaultPrevented` is true to maintain 100% test coverage on the conditional prevention logic.
diff --git a/.jules/palette.md b/.jules/palette.md
deleted file mode 100644
index c05638899..000000000
--- a/.jules/palette.md
+++ /dev/null
@@ -1,3 +0,0 @@
-## 2024-05-19 - Replace HTML disabled with aria-disabled="true" for Accessible Tooltips
-**Learning:** Native HTML `disabled` attributes completely hide elements from screen readers and block all pointer/hover events, preventing tooltips from functioning for disabled elements.
-**Action:** Replace `disabled` with `aria-disabled="true"`, enforce block click handlers via `e.preventDefault()`, and add a title tooltip directly to the element to maintain full tooltip accessibility and keyboard focus support for visually impaired and mouse users.
diff --git a/apps/desktop/src/features/score/ScoreView.test.tsx b/apps/desktop/src/features/score/ScoreView.test.tsx
index de4ccb95c..e47af9e94 100644
--- a/apps/desktop/src/features/score/ScoreView.test.tsx
+++ b/apps/desktop/src/features/score/ScoreView.test.tsx
@@ -1,4 +1,4 @@
-import { act, fireEvent, render, screen, waitFor } from "@testing-library/react";
+import { act, createEvent, fireEvent, render, screen, waitFor } from "@testing-library/react";
 import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
 import type { RehearsalSong, ScoreAttachment } from "@bandscope/shared-types";
 import { invoke } from "@tauri-apps/api/core";
@@ -95,11 +95,24 @@ describe("ScoreView", () => {
     render(<ScoreView song={song} projectId={null} onSongUpdate={vi.fn()} />);
 
     expect(screen.getByText("Scores attach to the active analysis project.")).toBeInTheDocument();
-    expect(screen.getByRole("button", { name: "Add score" })).toBeDisabled();
-    expect(screen.getByRole("button", { name: "Open score: opener.pdf" })).toBeDisabled();
-    expect(screen.getByRole("button", { name: "Remove: opener.pdf" })).toBeDisabled();
-
-    fireEvent.click(screen.getByRole("button", { name: "Open score: opener.pdf" }));
+    const addBtn = screen.getByRole("button", { name: "Add score" });
+    expect(addBtn).toHaveAttribute("aria-disabled", "true");
+    const openBtn = screen.getByRole("button", { name: "Open score: opener.pdf" });
+    expect(openBtn).toHaveAttribute("aria-disabled", "true");
+    const removeBtn = screen.getByRole("button", { name: "Remove: opener.pdf" });
+    expect(removeBtn).toHaveAttribute("aria-disabled", "true");
+
+    const clickEvent1 = createEvent.click(addBtn);
+    fireEvent(addBtn, clickEvent1);
+    expect(clickEvent1.defaultPrevented).toBe(true);
+
+    const clickEvent2 = createEvent.click(openBtn);
+    fireEvent(openBtn, clickEvent2);
+    expect(clickEvent2.defaultPrevented).toBe(true);
+
+    const clickEvent3 = createEvent.click(removeBtn);
+    fireEvent(removeBtn, clickEvent3);
+    expect(clickEvent3.defaultPrevented).toBe(true);
     expect(mockInvoke).not.toHaveBeenCalled();
   });
 
diff --git a/apps/desktop/src/features/score/ScoreView.tsx b/apps/desktop/src/features/score/ScoreView.tsx
index 72732450f..9b5c1aa01 100644
--- a/apps/desktop/src/features/score/ScoreView.tsx
+++ b/apps/desktop/src/features/score/ScoreView.tsx
@@ -134,8 +134,15 @@ export function ScoreView({ song, projectId, onSongUpdate }: ScoreViewProps) {
               <p className="mt-1 max-w-2xl text-sm text-slate-400">{t("scoreViewSubtitle")}</p>
             </div>
             <Button
-              onClick={projectId ? () => void handleAttach(projectId) : undefined}
-              disabled={!projectId || isAttaching}
+              onClick={(e) => {
+                if (!projectId || isAttaching) {
+                  e.preventDefault();
+                  return;
+                }
+                void handleAttach(projectId);
+              }}
+              aria-disabled={!projectId || isAttaching ? "true" : undefined}
+              title={!projectId ? t("scoreRequiresProject") : undefined}
               variant="secondary"
               className="min-h-11 border border-cyan-300/20 bg-cyan-300/10 font-semibold text-cyan-50 hover:bg-cyan-300/20"
             >
@@ -183,11 +190,18 @@ export function ScoreView({ song, projectId, onSongUpdate }: ScoreViewProps) {
                   >
                     <button
                       type="button"
-                      onClick={projectId ? () => void openAttachment(projectId, attachment) : undefined}
-                      disabled={!projectId}
+                      onClick={(e) => {
+                        if (!projectId) {
+                          e.preventDefault();
+                          return;
+                        }
+                        void openAttachment(projectId, attachment);
+                      }}
+                      aria-disabled={!projectId ? "true" : undefined}
                       aria-current={selected?.id === attachment.id ? "true" : undefined}
                       aria-label={`${t("scoreOpen")}: ${attachment.fileName}`}
-                      className="flex min-h-10 min-w-0 flex-1 items-center gap-2 text-left text-sm font-semibold text-slate-100 focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-cyan-300 disabled:cursor-not-allowed disabled:opacity-60"
+                      title={!projectId ? t("scoreRequiresProject") : `${t("scoreOpen")}: ${attachment.fileName}`}
+                      className="flex min-h-10 min-w-0 flex-1 items-center gap-2 text-left text-sm font-semibold text-slate-100 focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-cyan-300 aria-disabled:cursor-not-allowed aria-disabled:opacity-60"
                     >
                       <FileMusic className="size-4 shrink-0 text-cyan-300" aria-hidden="true" />
                       <span className="truncate">{attachment.fileName}</span>
@@ -195,9 +209,16 @@ export function ScoreView({ song, projectId, onSongUpdate }: ScoreViewProps) {
                     <Button
                       variant="outline"
                       size="icon"
-                      onClick={projectId ? () => void handleRemove(projectId, attachment) : undefined}
-                      disabled={!projectId}
+                      onClick={(e) => {
+                        if (!projectId) {
+                          e.preventDefault();
+                          return;
+                        }
+                        void handleRemove(projectId, attachment);
+                      }}
+                      aria-disabled={!projectId ? "true" : undefined}
                       aria-label={`${t("scoreRemove")}: ${attachment.fileName}`}
+                      title={!projectId ? t("scoreRequiresProject") : `${t("scoreRemove")}: ${attachment.fileName}`}
                       className="size-10 border-rose-300/25 text-rose-200 hover:bg-rose-400/10"
                     >
                       <Trash2 className="size-4" aria-hidden="true" />
diff --git a/apps/desktop/src/features/score/ScoreViewer.test.tsx b/apps/desktop/src/features/score/ScoreViewer.test.tsx
index 3ac2dd605..709b8c76e 100644
--- a/apps/desktop/src/features/score/ScoreViewer.test.tsx
+++ b/apps/desktop/src/features/score/ScoreViewer.test.tsx
@@ -1,4 +1,4 @@
-import { act, fireEvent, render, screen, waitFor } from "@testing-library/react";
+import { act, createEvent, fireEvent, render, screen, waitFor } from "@testing-library/react";
 import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
 import type { PDFDocumentLoadingTask, PDFDocumentProxy } from "pdfjs-dist";
 import { ScoreViewer } from "./ScoreViewer";
@@ -120,7 +120,13 @@ describe("ScoreViewer", () => {
       expect(page.render).toHaveBeenCalled();
     });
     expect(page.getViewport).toHaveBeenCalledWith({ scale: 1 });
-    expect(screen.getByRole("button", { name: "Previous page" })).toBeDisabled();
+    const previousButton = screen.getByRole("button", { name: "Previous page" });
+    expect(previousButton).toHaveAttribute("aria-disabled", "true");
+
+    const clickEvent = createEvent.click(previousButton);
+    fireEvent(previousButton, clickEvent);
+    expect(clickEvent.defaultPrevented).toBe(true);
+
     expect(screen.getByRole("button", { name: "Next page" })).toBeEnabled();
   });
 
@@ -174,14 +180,14 @@ describe("ScoreViewer", () => {
     expect(await screen.findByText("Page 1 of 3")).toBeInTheDocument();
     const previousButton = screen.getByRole("button", { name: "Previous page" });
     const nextButton = screen.getByRole("button", { name: "Next page" });
-    expect(previousButton).toBeDisabled();
+    expect(previousButton).toHaveAttribute("aria-disabled", "true");
 
     fireEvent.click(nextButton);
     expect(screen.getByText("Page 2 of 3")).toBeInTheDocument();
 
     fireEvent.click(nextButton);
     expect(screen.getByText("Page 3 of 3")).toBeInTheDocument();
-    expect(nextButton).toBeDisabled();
+    expect(nextButton).toHaveAttribute("aria-disabled", "true");
 
     await waitFor(() => {
       expect(doc.getPage).toHaveBeenCalledWith(3);
diff --git a/apps/desktop/src/features/score/ScoreViewer.tsx b/apps/desktop/src/features/score/ScoreViewer.tsx
index 82692469e..332bb4dd5 100644
--- a/apps/desktop/src/features/score/ScoreViewer.tsx
+++ b/apps/desktop/src/features/score/ScoreViewer.tsx
@@ -258,6 +258,7 @@ export function ScoreViewer({ data, fileName, onStatusChange }: ScoreViewerProps
               size="icon-lg"
               className="size-12"
               aria-label={t("scoreViewerZoomOut")}
+              title={t("scoreViewerZoomOut")}
               onClick={zoomOut}
             >
               <ZoomOut aria-hidden="true" />
@@ -267,6 +268,7 @@ export function ScoreViewer({ data, fileName, onStatusChange }: ScoreViewerProps
               size="icon-lg"
               className="size-12"
               aria-label={t("scoreViewerZoomIn")}
+              title={t("scoreViewerZoomIn")}
               onClick={zoomIn}
             >
               <ZoomIn aria-hidden="true" />
@@ -292,8 +294,15 @@ export function ScoreViewer({ data, fileName, onStatusChange }: ScoreViewerProps
             size="icon-lg"
             className="size-14"
             aria-label={t("scoreViewerPrevPage")}
-            disabled={pageNumber <= 1}
-            onClick={goToPreviousPage}
+            title={t("scoreViewerPrevPage")}
+            aria-disabled={pageNumber <= 1 ? "true" : undefined}
+            onClick={(e) => {
+              if (pageNumber <= 1) {
+                e.preventDefault();
+                return;
+              }
+              goToPreviousPage();
+            }}
           >
             <ChevronLeft className="size-6" aria-hidden="true" />
           </Button>
@@ -305,8 +314,15 @@ export function ScoreViewer({ data, fileName, onStatusChange }: ScoreViewerProps
             size="icon-lg"
             className="size-14"
             aria-label={t("scoreViewerNextPage")}
-            disabled={pageNumber >= pageCount}
-            onClick={goToNextPage}
+            title={t("scoreViewerNextPage")}
+            aria-disabled={pageNumber >= pageCount ? "true" : undefined}
+            onClick={(e) => {
+              if (pageNumber >= pageCount) {
+                e.preventDefault();
+                return;
+              }
+              goToNextPage();
+            }}
           >
             <ChevronRight className="size-6" aria-hidden="true" />
           </Button>