fix: respect macos header double click action

src-tauri/src/commands/system.rs

@@ -1,3 +1,6 @@
+#[cfg(desktop)]
+use std::process::Command;
+
 #[cfg(desktop)]
 use crate::menu;
 use crate::settings::Settings;
@@ -13,6 +16,76 @@ use tauri::Window;
 
 use super::parse_build_label;
 
+#[cfg(desktop)]
+#[derive(Clone, Copy, Debug, Eq, PartialEq)]
+enum TitleBarDoubleClickAction {
+    Fill,
+    Minimize,
+    None,
+}
+
+#[cfg(desktop)]
+fn parse_title_bar_double_click_action(value: &str) -> Option<TitleBarDoubleClickAction> {
+    match value.trim().to_ascii_lowercase().as_str() {
+        "fill" | "zoom" | "maximize" => Some(TitleBarDoubleClickAction::Fill),
+        "minimize" => Some(TitleBarDoubleClickAction::Minimize),
+        "none" | "no action" | "do nothing" => Some(TitleBarDoubleClickAction::None),
+        _ => None,
+    }
+}
+
+#[cfg(desktop)]
+fn parse_legacy_title_bar_double_click_action(value: &str) -> Option<TitleBarDoubleClickAction> {
+    match value.trim().to_ascii_lowercase().as_str() {
+        "1" | "true" | "yes" => Some(TitleBarDoubleClickAction::Minimize),
+        "0" | "false" | "no" => Some(TitleBarDoubleClickAction::Fill),
+        _ => None,
+    }
+}
+
+#[cfg(desktop)]
+fn read_global_defaults_value(key: &str) -> Option<String> {
+    let output = Command::new("defaults")
+        .args(["read", "-g", key])
+        .output()
+        .ok()?;
+    if !output.status.success() {
+        return None;
+    }
+
+    let value = String::from_utf8(output.stdout).ok()?;
+    let trimmed = value.trim();
+    if trimmed.is_empty() {
+        return None;
+    }
+
+    Some(trimmed.to_string())
+}
+
+#[cfg(desktop)]
+fn resolve_title_bar_double_click_action(
+    read_value: impl Fn(&str) -> Option<String>,
+) -> TitleBarDoubleClickAction {
+    read_value("AppleActionOnDoubleClick")
+        .as_deref()
+        .and_then(parse_title_bar_double_click_action)
+        .or_else(|| {
+            read_value("AppleMiniaturizeOnDoubleClick")
+                .as_deref()
+                .and_then(parse_legacy_title_bar_double_click_action)
+        })
+        .unwrap_or(TitleBarDoubleClickAction::Fill)
+}
+
+#[cfg(desktop)]
+fn toggle_window_fill(window: &Window) -> Result<(), String> {
+    if window.is_maximized().map_err(|e| e.to_string())? {
+        window.unmaximize().map_err(|e| e.to_string())
+    } else {
+        window.maximize().map_err(|e| e.to_string())
+    }
+}
+
 // ── MCP commands (desktop) ──────────────────────────────────────────────────
 
 #[cfg(desktop)]
@@ -153,6 +226,16 @@ pub fn update_current_window_min_size(
         .map_err(|e| e.to_string())
 }
 
+#[cfg(desktop)]
+#[tauri::command]
+pub fn perform_current_window_titlebar_double_click(window: Window) -> Result<(), String> {
+    match resolve_title_bar_double_click_action(read_global_defaults_value) {
+        TitleBarDoubleClickAction::Fill => toggle_window_fill(&window),
+        TitleBarDoubleClickAction::Minimize => window.minimize().map_err(|e| e.to_string()),
+        TitleBarDoubleClickAction::None => Ok(()),
+    }
+}
+
 #[cfg(mobile)]
 #[tauri::command]
 pub fn update_current_window_min_size(
@@ -164,6 +247,12 @@ pub fn update_current_window_min_size(
     Ok(())
 }
 
+#[cfg(mobile)]
+#[tauri::command]
+pub fn perform_current_window_titlebar_double_click(_window: tauri::Window) -> Result<(), String> {
+    Ok(())
+}
+
 // ── Settings & config commands ──────────────────────────────────────────────
 
 #[tauri::command]
@@ -242,3 +331,56 @@ pub fn load_vault_list() -> Result<VaultList, String> {
 pub fn save_vault_list(list: VaultList) -> Result<(), String> {
     vault_list::save_vault_list(&list)
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn parses_current_title_bar_actions() {
+        assert_eq!(
+            parse_title_bar_double_click_action("Fill"),
+            Some(TitleBarDoubleClickAction::Fill)
+        );
+        assert_eq!(
+            parse_title_bar_double_click_action("zoom"),
+            Some(TitleBarDoubleClickAction::Fill)
+        );
+        assert_eq!(
+            parse_title_bar_double_click_action("Minimize"),
+            Some(TitleBarDoubleClickAction::Minimize)
+        );
+        assert_eq!(
+            parse_title_bar_double_click_action("No Action"),
+            Some(TitleBarDoubleClickAction::None)
+        );
+    }
+
+    #[test]
+    fn resolves_current_setting_before_legacy_fallback() {
+        let action = resolve_title_bar_double_click_action(|key| match key {
+            "AppleActionOnDoubleClick" => Some("No Action".to_string()),
+            "AppleMiniaturizeOnDoubleClick" => Some("1".to_string()),
+            _ => None,
+        });
+
+        assert_eq!(action, TitleBarDoubleClickAction::None);
+    }
+
+    #[test]
+    fn falls_back_to_legacy_minimize_setting() {
+        let action = resolve_title_bar_double_click_action(|key| match key {
+            "AppleMiniaturizeOnDoubleClick" => Some("1".to_string()),
+            _ => None,
+        });
+
+        assert_eq!(action, TitleBarDoubleClickAction::Minimize);
+    }
+
+    #[test]
+    fn defaults_to_fill_when_no_setting_is_available() {
+        let action = resolve_title_bar_double_click_action(|_| None);
+
+        assert_eq!(action, TitleBarDoubleClickAction::Fill);
+    }
+}

src-tauri/src/lib.rs

@@ -254,6 +254,7 @@ macro_rules! app_invoke_handler {
             commands::update_menu_state,
             commands::trigger_menu_command,
             commands::update_current_window_min_size,
+            commands::perform_current_window_titlebar_double_click,
             commands::save_settings,
             commands::download_and_install_app_update,
             commands::load_vault_list,

src/components/BreadcrumbBar.test.tsx

@@ -3,6 +3,12 @@ import { describe, it, expect, vi } from 'vitest'
 import { BreadcrumbBar } from './BreadcrumbBar'
 import type { VaultEntry } from '../types'
 
+const dragRegionMouseDown = vi.fn()
+
+vi.mock('../hooks/useDragRegion', () => ({
+  useDragRegion: () => ({ onMouseDown: dragRegionMouseDown }),
+}))
+
 const baseEntry: VaultEntry = {
   path: '/vault/note/test.md',
   filename: 'test.md',
@@ -63,6 +69,15 @@ async function expectTooltip(trigger: HTMLElement, ...parts: string[]) {
 }
 
 describe('BreadcrumbBar — drag region', () => {
+  it('forwards mousedown events to the shared drag-region hook', () => {
+    const { container } = render(<BreadcrumbBar entry={baseEntry} {...defaultProps} />)
+    const bar = container.querySelector('.breadcrumb-bar') as HTMLElement
+
+    fireEvent.mouseDown(bar, { button: 0 })
+
+    expect(dragRegionMouseDown).toHaveBeenCalledOnce()
+  })
+
   it('has data-tauri-drag-region on the container', () => {
     const { container } = render(<BreadcrumbBar entry={baseEntry} {...defaultProps} />)
     const bar = container.firstElementChild as HTMLElement

src/components/BreadcrumbBar.tsx

@@ -19,6 +19,7 @@ import {
 } from '@phosphor-icons/react'
 import { NoteTitleIcon } from './NoteTitleIcon'
 import { slugify } from '../hooks/useNoteCreation'
+import { useDragRegion } from '../hooks/useDragRegion'
 
 interface BreadcrumbBarProps {
   entry: VaultEntry
@@ -501,12 +502,15 @@ export const BreadcrumbBar = memo(function BreadcrumbBar({
   onRenameFilename,
   ...actionProps
 }: BreadcrumbBarProps) {
+  const { onMouseDown } = useDragRegion()
+
   return (
     <TooltipProvider>
       <div
         ref={barRef}
         data-tauri-drag-region
         data-title-hidden=""
+        onMouseDown={onMouseDown}
         className="breadcrumb-bar flex shrink-0 items-center border-b border-transparent"
         style={{
           height: 52,

src/hooks/useDragRegion.test.tsx

@@ -2,7 +2,14 @@ import { fireEvent, render, screen } from '@testing-library/react'
 import { beforeEach, describe, expect, it, vi } from 'vitest'
 import { useDragRegion } from './useDragRegion'
 
-const startDragging = vi.fn().mockResolvedValue(undefined)
+const { invoke, startDragging } = vi.hoisted(() => ({
+  invoke: vi.fn().mockResolvedValue(undefined),
+  startDragging: vi.fn().mockResolvedValue(undefined),
+}))
+
+vi.mock('@tauri-apps/api/core', () => ({
+  invoke,
+}))
 
 vi.mock('@tauri-apps/api/window', () => ({
   getCurrentWindow: () => ({ startDragging }),
@@ -31,6 +38,16 @@ describe('useDragRegion', () => {
     fireEvent.mouseDown(screen.getByTestId('drag-surface'), { button: 0 })
 
     expect(startDragging).toHaveBeenCalledOnce()
+    expect(invoke).not.toHaveBeenCalled()
+  })
+
+  it('runs the native title-bar action on a double-click', () => {
+    render(<DragRegionHarness />)
+
+    fireEvent.mouseDown(screen.getByTestId('drag-surface'), { button: 0, detail: 2 })
+
+    expect(invoke).toHaveBeenCalledWith('perform_current_window_titlebar_double_click')
+    expect(startDragging).not.toHaveBeenCalled()
   })
 
   it('does not start dragging from no-drag containers', () => {
@@ -39,6 +56,7 @@ describe('useDragRegion', () => {
     fireEvent.mouseDown(screen.getByTestId('no-drag-card'), { button: 0 })
 
     expect(startDragging).not.toHaveBeenCalled()
+    expect(invoke).not.toHaveBeenCalled()
   })
 
   it('does not start dragging from interactive descendants', () => {
@@ -47,6 +65,7 @@ describe('useDragRegion', () => {
     fireEvent.mouseDown(screen.getByRole('button', { name: 'Action' }), { button: 0 })
 
     expect(startDragging).not.toHaveBeenCalled()
+    expect(invoke).not.toHaveBeenCalled()
   })
 
   it('ignores non-primary mouse buttons', () => {
@@ -55,5 +74,6 @@ describe('useDragRegion', () => {
     fireEvent.mouseDown(screen.getByTestId('drag-surface'), { button: 1 })
 
     expect(startDragging).not.toHaveBeenCalled()
+    expect(invoke).not.toHaveBeenCalled()
   })
 })

src/hooks/useDragRegion.ts

@@ -1,5 +1,16 @@
-import { useCallback } from 'react'
+import { invoke } from '@tauri-apps/api/core'
 import { getCurrentWindow } from '@tauri-apps/api/window'
+import { useCallback } from 'react'
+
+const NO_DRAG_SELECTOR = 'button, input, select, a, [data-no-drag]'
+
+function isDragDisabledTarget(target: EventTarget | null): boolean {
+  return target instanceof Element && target.closest(NO_DRAG_SELECTOR) !== null
+}
+
+function performCurrentWindowTitlebarDoubleClick(): Promise<void> {
+  return invoke<void>('perform_current_window_titlebar_double_click')
+}
 
 /**
  * Returns a mousedown handler that triggers Tauri window drag via startDragging().
@@ -8,10 +19,13 @@ import { getCurrentWindow } from '@tauri-apps/api/window'
 export function useDragRegion() {
   const onMouseDown = useCallback((e: React.MouseEvent) => {
     if (e.button !== 0) return
-    const target = e.target as HTMLElement
-    if (target.closest('button, input, select, a, [data-no-drag]')) return
+    if (isDragDisabledTarget(e.target)) return
     e.preventDefault()
-    getCurrentWindow().startDragging().catch(() => { /* ignore */ })
+    if (e.detail === 2) {
+      void performCurrentWindowTitlebarDoubleClick().catch(() => {})
+      return
+    }
+    void getCurrentWindow().startDragging().catch(() => {})
   }, [])
 
   return { onMouseDown }