fix(macos): forward back/forward mouse buttons in capture and emulation (#392)

* fix(macos): forward back/forward mouse buttons in capture and emulation

OtherMouseDown/Up events on macOS carry a button number field that
distinguishes middle (2), back (3), and forward (4) buttons. The
capture backend was unconditionally mapping all OtherMouse events to
BTN_MIDDLE, silently dropping back/forward. The emulation backend had
no match arms for BTN_BACK/BTN_FORWARD, causing them to be dropped
with a warning.

Fix capture by reading MOUSE_EVENT_BUTTON_NUMBER and mapping 3->BTN_BACK,
4->BTN_FORWARD. Fix emulation by adding match arms for BTN_BACK/BTN_FORWARD
and setting MOUSE_EVENT_BUTTON_NUMBER on the emitted CGEvent so macOS
apps receive the correct button identity.

* fix(macos): track button state and double-clicks by evdev code instead of CGMouseButton

Back, forward, and middle buttons all map to CGMouseButton::Center on
macOS, which caused them to share a single pressed-state boolean and
alias in double-click detection. Replace the ButtonState struct with a
HashSet<u32> keyed by evdev button code so each button is tracked
independently.

---------

Co-authored-by: Ferdinand Schober <ferdinandschober20@gmail.com>

.github/workflows/cachix.yml

@@ -1,40 +1,46 @@
-name: Binary Cache
+name: Nix Binary Cache
+
+on:
+  push:
+    branches: ["main"]
+  pull_request:
+    branches: ["main"]
+  workflow_dispatch:
 
-on: [push, pull_request, workflow_dispatch]
 jobs:
   nix:
     strategy:
       matrix:
-       os: 
+        os:
-        - ubuntu-latest
+          - ubuntu-latest
-        - macos-15-intel
+          - macos-15-intel
-        - macos-14
+          - macos-latest
     name: "Build"
-    runs-on: ${{ matrix.os }} 
+    runs-on: ${{ matrix.os }}
     steps:
-    - name: Checkout
+      - name: Checkout
-      uses: actions/checkout@v4
+        uses: actions/checkout@v4
-      with:
+        with:
-        submodules: recursive
+          submodules: recursive
 
-    - uses: DeterminateSystems/nix-installer-action@main
+      # - uses: DeterminateSystems/nix-installer-action@main
-      with:
+      #   with:
-        logger: pretty
+      #     logger: pretty
-    - uses: DeterminateSystems/magic-nix-cache-action@main
+      # - uses: DeterminateSystems/magic-nix-cache-action@main
-    - uses: cachix/cachix-action@v14
+      - uses: cachix/install-nix-action@v31
-      with:
+      - uses: cachix/cachix-action@v16
-        name: lan-mouse
+        with:
-        authToken: '${{ secrets.CACHIX_AUTH_TOKEN }}'
+          name: lan-mouse
+          authToken: "${{ secrets.CACHIX_AUTH_TOKEN }}"
 
-    - name: Build lan-mouse (x86_64-linux)
+      - name: Build lan-mouse (x86_64-linux)
-      if: matrix.os == 'ubuntu-latest'
+        if: matrix.os == 'ubuntu-latest'
-      run: nix build --print-build-logs --show-trace .#packages.x86_64-linux.lan-mouse
+        run: nix build --print-build-logs --show-trace .#packages.x86_64-linux.lan-mouse
 
-    - name: Build lan-mouse (x86_64-darwin)
+      - name: Build lan-mouse (x86_64-darwin)
-      if: matrix.os == 'macos-15-intel'
+        if: matrix.os == 'macos-15-intel'
-      run: nix build --print-build-logs --show-trace .#packages.x86_64-darwin.lan-mouse
+        run: nix build --print-build-logs --show-trace .#packages.x86_64-darwin.lan-mouse
-
-    - name: Build lan-mouse (aarch64-darwin)
-      if: matrix.os == 'macos-14'
-      run: nix build --print-build-logs --show-trace .#packages.aarch64-darwin.lan-mouse
 
+      - name: Build lan-mouse (aarch64-darwin)
+        if: matrix.os == 'macos-latest'
+        run: nix build --print-build-logs --show-trace .#packages.aarch64-darwin.lan-mouse

.github/workflows/pre-release.yml

@@ -11,7 +11,7 @@ env:
 
 jobs:
   linux-release-build:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-22.04
     steps:
     - uses: actions/checkout@v4
     - name: install dependencies

.github/workflows/rust.yml

@@ -10,149 +10,87 @@ env:
   CARGO_TERM_COLOR: always
 
 jobs:
-  build-linux:
+  fmt:
-
+    name: Formatting
     runs-on: ubuntu-latest
-
     steps:
-    - uses: actions/checkout@v4
+      - uses: actions/checkout@v4
-    - name: install dependencies
+      - name: cargo fmt
-      run: |
+        run: cargo fmt --check
-        sudo apt-get update
-        sudo apt-get install libx11-dev libxtst-dev
-        sudo apt-get install libadwaita-1-dev libgtk-4-dev
-    - name: Build
-      run: cargo build --verbose
-    - name: Run tests
-      run: cargo test --verbose
-    - name: Check Formatting
-      run: cargo fmt --check
-    - name: Clippy
-      run: cargo clippy --all-features --all-targets -- --deny warnings
-    - name: Upload build artifact
-      uses: actions/upload-artifact@v4
-      with:
-        name: lan-mouse
-        path: target/debug/lan-mouse
-
-  build-windows:
-
-    runs-on: windows-latest
 
+  ci:
+    name: ${{ matrix.job }} ${{ matrix.os }}
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        os:
+          - ubuntu-latest
+          - windows-latest
+          - macos-latest
+          - macos-15-intel
+        job:
+          - build
+          - check
+          - clippy
+          - test
     steps:
-    - uses: actions/checkout@v4
+      - uses: actions/checkout@v4
-    - uses: actions/setup-python@v5
+      - uses: Swatinem/rust-cache@v2
-      with:
+      - name: Install Linux deps
-        python-version: '3.11'
+        if: runner.os == 'Linux'
-    # needed for cache restore
+        run: |
-    - name: create gtk dir
+          sudo apt-get update
-      run: mkdir C:\gtk-build\gtk\x64\release
+          sudo apt-get install libx11-dev libxtst-dev libadwaita-1-dev libgtk-4-dev
-    - uses: actions/cache@v3
+      - name: Install macOS dependencies
-      id: cache
+        if: runner.os == 'macOS'
-      with:
+        run: brew install gtk4 libadwaita imagemagick
-        path: c:/gtk-build/gtk/x64/release/**
+      - name: Install Windows Dependencies - create gtk dir
-        key: gtk-windows-build
+        if: runner.os == 'Windows'
-        restore-keys: gtk-windows-build
+        run: mkdir C:\gtk-build\gtk\x64\release
-    - name: Update path
+      - name: Install Windows Dependencies - install gtk from cache
-      run: |
+        uses: actions/cache@v3
-        echo "PKG_CONFIG=C:\gtk-build\gtk\x64\release\bin\pkgconf.exe" | Out-File -FilePath $env:GITHUB_ENV -Encoding utf8 -Append
+        if: runner.os == 'Windows'
-        echo "C:\pkg-config-lite-0.28-1\bin" | Out-File -FilePath $env:GITHUB_PATH -Encoding utf8 -Append
+        id: cache
-        echo "C:\gtk-build\gtk\x64\release\bin" | Out-File -FilePath $env:GITHUB_PATH -Encoding utf8 -Append
+        with:
-        echo $env:GITHUB_PATH
+          path: c:/gtk-build/gtk/x64/release/**
-        echo $env:PATH
+          key: gtk-windows-build
-    - name: Install dependencies
+          restore-keys: gtk-windows-build
-      if: steps.cache.outputs.cache-hit != 'true'
+      - name: Install Windows Dependencies - update PATH
-      run: |
+        if: runner.os == 'Windows'
-        # choco install msys2
+        run: |
-        # choco install visualstudio2022-workload-vctools
+          echo "PKG_CONFIG=C:\gtk-build\gtk\x64\release\bin\pkgconf.exe" | Out-File -FilePath $env:GITHUB_ENV -Encoding utf8 -Append
-        # choco install pkgconfiglite
+          echo "C:\pkg-config-lite-0.28-1\bin" | Out-File -FilePath $env:GITHUB_PATH -Encoding utf8 -Append
-        py -m venv .venv
+          echo "C:\gtk-build\gtk\x64\release\bin" | Out-File -FilePath $env:GITHUB_PATH -Encoding utf8 -Append
-        .venv\Scripts\activate.ps1
+          echo $env:GITHUB_PATH
-        py -m pip install gvsbuild
+          echo $env:PATH
-        # see https://github.com/wingtk/gvsbuild/pull/1004
+      - name: Install Windows dependencies - build gtk
-        Move-Item "C:\Program Files\Git\usr\bin" "C:\Program Files\Git\usr\notbin"
+        if: runner.os == 'Windows' && steps.cache.outputs.cache-hit != 'true'
-        Move-Item "C:\Program Files\Git\bin" "C:\Program Files\Git\notbin"
+        run: |
-        gvsbuild build --msys-dir=C:\msys64 gtk4 libadwaita librsvg
+          # choco install msys2
-        Move-Item "C:\Program Files\Git\usr\notbin" "C:\Program Files\Git\usr\bin"
+          # choco install visualstudio2022-workload-vctools
-        Move-Item "C:\Program Files\Git\notbin" "C:\Program Files\Git\bin"
+          # choco install pkgconfiglite
-    - name: Build
+          py -m venv .venv
-      run: cargo build --verbose
+          .venv\Scripts\activate.ps1
-    - name: Run tests
+          py -m pip install gvsbuild
-      run: cargo test --verbose
+          gvsbuild build --msys-dir=C:\msys64 gtk4 libadwaita librsvg
-    - name: Check Formatting
+      - name: cargo build
-      run: cargo fmt --check
+        if: matrix.job == 'build'
-    - name: Clippy
+        run: cargo build
-      run: cargo clippy --all-features --all-targets -- --deny warnings
-    - name: Copy Gtk Dlls
-      run: Get-Childitem -Path "C:\\gtk-build\\gtk\\x64\\release\\bin\\*.dll" -File -Recurse | Copy-Item -Destination "target\\debug"
-    - name: Upload build artifact
-      uses: actions/upload-artifact@v4
-      with:
-        name: lan-mouse-windows
-        path: |
-          target/debug/lan-mouse.exe
-          target/debug/*.dll
 
-  build-macos:
+      - name: cargo check
-    runs-on: macos-15-intel
+        if: matrix.job == 'check'
-    steps:
+        run: cargo check --workspace --all-targets --all-features
-    - uses: actions/checkout@v4
-    - name: install dependencies
-      run: brew install gtk4 libadwaita imagemagick
-    - name: Build
-      run: cargo build --verbose
-    - name: Run tests
-      run: cargo test --verbose
-    - name: Check Formatting
-      run: cargo fmt --check
-    - name: Clippy
-      run: cargo clippy --all-features --all-targets -- --deny warnings
-    - name: Make icns
-      run: scripts/makeicns.sh
-    - name: Install cargo bundle
-      run: cargo install cargo-bundle
-    - name: Bundle
-      run: |
-        cargo bundle
-        scripts/copy-macos-dylib.sh
-    - name: Zip bundle
-      run: |
-        cd target/debug/bundle/osx
-        zip -r "Lan Mouse macOS (Intel).zip" "Lan Mouse.app"
-    - name: Upload build artifact
-      uses: actions/upload-artifact@v4
-      with:
-        name: Lan Mouse macOS (Intel)
-        path: target/debug/bundle/osx/Lan Mouse macOS (Intel).zip
 
-  build-macos-aarch64:
+      - name: cargo test
-    runs-on: macos-14
+        if: matrix.job == 'test'
-    steps:
+        run: cargo test --workspace --all-features
-    - uses: actions/checkout@v4
+
-    - name: install dependencies
+      - name: cargo clippy
-      run: brew install gtk4 libadwaita imagemagick
+        if: matrix.job == 'clippy'
-    - name: Build
+        run: cargo clippy --workspace --all-targets --all-features -- -D warnings
-      run: cargo build --verbose
+
-    - name: Run tests
+      - uses: clechasseur/rs-clippy-check@v4
-      run: cargo test --verbose
+        if: matrix.job == 'clippy'
-    - name: Check Formatting
+        with:
-      run: cargo fmt --check
+          args: --workspace --all-targets --all-features
-    - name: Clippy
-      run: cargo clippy --all-features --all-targets -- --deny warnings
-    - name: Make icns
-      run: scripts/makeicns.sh
-    - name: Install cargo bundle
-      run: cargo install cargo-bundle
-    - name: Bundle
-      run: |
-        cargo bundle
-        scripts/copy-macos-dylib.sh
-    - name: Zip bundle
-      run: |
-        cd target/debug/bundle/osx
-        zip -r "Lan Mouse macOS (ARM).zip" "Lan Mouse.app"
-    - name: Upload build artifact
-      uses: actions/upload-artifact@v4
-      with:
-        name: Lan Mouse macOS (ARM)
-        path: target/debug/bundle/osx/Lan Mouse macOS (ARM).zip

.github/workflows/tagged-release.yml

@@ -7,7 +7,7 @@ on:
 
 jobs:
   linux-release-build:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-22.04
     steps:
     - uses: actions/checkout@v4
     - name: install dependencies

input-capture/src/macos.rs

@@ -18,7 +18,9 @@ use core_graphics::{
     event_source::{CGEventSource, CGEventSourceStateID},
 };
 use futures_core::Stream;
-use input_event::{BTN_LEFT, BTN_MIDDLE, BTN_RIGHT, Event, KeyboardEvent, PointerEvent};
+use input_event::{
+    BTN_BACK, BTN_FORWARD, BTN_LEFT, BTN_MIDDLE, BTN_RIGHT, Event, KeyboardEvent, PointerEvent,
+};
 use keycode::{KeyMap, KeyMapping};
 use libc::c_void;
 use once_cell::unsync::Lazy;
@@ -304,16 +306,28 @@ fn get_events(
             })))
         }
         CGEventType::OtherMouseDown => {
+            let btn_num = ev.get_integer_value_field(EventField::MOUSE_EVENT_BUTTON_NUMBER);
+            let button = match btn_num {
+                3 => BTN_BACK,
+                4 => BTN_FORWARD,
+                _ => BTN_MIDDLE,
+            };
             result.push(CaptureEvent::Input(Event::Pointer(PointerEvent::Button {
                 time: 0,
-                button: BTN_MIDDLE,
+                button,
                 state: 1,
             })))
         }
         CGEventType::OtherMouseUp => {
+            let btn_num = ev.get_integer_value_field(EventField::MOUSE_EVENT_BUTTON_NUMBER);
+            let button = match btn_num {
+                3 => BTN_BACK,
+                4 => BTN_FORWARD,
+                _ => BTN_MIDDLE,
+            };
             result.push(CaptureEvent::Input(Event::Pointer(PointerEvent::Button {
                 time: 0,
-                button: BTN_MIDDLE,
+                button,
                 state: 0,
             })))
         }

input-emulation/src/libei.rs

@@ -1,7 +1,8 @@
 use futures::{StreamExt, future};
 use std::{
-    io,
+    env, fs, io,
     os::{fd::OwnedFd, unix::net::UnixStream},
+    path::PathBuf,
     sync::{
         Arc, Mutex, RwLock,
         atomic::{AtomicBool, Ordering},
@@ -50,10 +51,45 @@ pub(crate) struct LibeiEmulation<'a> {
     session: Session<'a, RemoteDesktop<'a>>,
 }
 
+/// Get the path to the RemoteDesktop token file
+fn get_token_file_path() -> PathBuf {
+    let cache_dir = env::var("XDG_CACHE_HOME")
+        .ok()
+        .map(PathBuf::from)
+        .unwrap_or_else(|| {
+            let home = env::var("HOME").expect("HOME not set");
+            PathBuf::from(home).join(".cache")
+        });
+
+    cache_dir.join("lan-mouse").join("remote-desktop.token")
+}
+
+/// Read the RemoteDesktop token from file
+fn read_token() -> Option<String> {
+    let token_path = get_token_file_path();
+    match fs::read_to_string(&token_path) {
+        Ok(token) => Some(token.trim().to_string()),
+        Err(_) => None,
+    }
+}
+
+/// Write the RemoteDesktop token to file
+fn write_token(token: &str) -> io::Result<()> {
+    let token_path = get_token_file_path();
+    if let Some(parent) = token_path.parent() {
+        fs::create_dir_all(parent)?;
+    }
+
+    fs::write(&token_path, token)?;
+    Ok(())
+}
+
 async fn get_ei_fd<'a>()
 -> Result<(RemoteDesktop<'a>, Session<'a, RemoteDesktop<'a>>, OwnedFd), ashpd::Error> {
     let remote_desktop = RemoteDesktop::new().await?;
 
+    let restore_token = read_token();
+
     log::debug!("creating session ...");
     let session = remote_desktop.create_session().await?;
 
@@ -62,13 +98,20 @@ async fn get_ei_fd<'a>()
         .select_devices(
             &session,
             DeviceType::Keyboard | DeviceType::Pointer,
-            None,
+            restore_token.as_deref(),
             PersistMode::ExplicitlyRevoked,
         )
         .await?;
 
     log::info!("requesting permission for input emulation");
-    let _devices = remote_desktop.start(&session, None).await?.response()?;
+    let start_response = remote_desktop.start(&session, None).await?.response()?;
+
+    // The restore token is only valid once, we need to re-save it each time
+    if let Some(token_str) = start_response.restore_token() {
+        if let Err(e) = write_token(token_str) {
+            log::warn!("failed to save RemoteDesktop token: {}", e);
+        }
+    }
 
     let fd = remote_desktop.connect_to_eis(&session).await?;
     Ok((remote_desktop, session, fd))

input-emulation/src/macos.rs

@@ -10,10 +10,13 @@ use core_graphics::event::{
     ScrollEventUnit,
 };
 use core_graphics::event_source::{CGEventSource, CGEventSourceStateID};
-use input_event::{BTN_LEFT, BTN_MIDDLE, BTN_RIGHT, Event, KeyboardEvent, PointerEvent, scancode};
+use input_event::{
+    BTN_BACK, BTN_FORWARD, BTN_LEFT, BTN_MIDDLE, BTN_RIGHT, Event, KeyboardEvent, PointerEvent,
+    scancode,
+};
 use keycode::{KeyMap, KeyMapping};
 use std::cell::Cell;
-use std::ops::{Index, IndexMut};
+use std::collections::HashSet;
 use std::rc::Rc;
 use std::sync::Arc;
 use std::time::{Duration, Instant};
@@ -30,10 +33,10 @@ pub(crate) struct MacOSEmulation {
     event_source: CGEventSource,
     /// task handle for key repeats
     repeat_task: Option<JoinHandle<()>>,
-    /// current state of the mouse buttons
+    /// current state of the mouse buttons (tracked by evdev button code)
-    button_state: ButtonState,
+    pressed_buttons: HashSet<u32>,
-    /// button previously pressed
+    /// button previously pressed (evdev button code)
-    previous_button: Option<CGMouseButton>,
+    previous_button: Option<u32>,
     /// timestamp of previous click (button down)
     previous_button_click: Option<Instant>,
     /// click state, i.e. number of clicks in quick succession
@@ -44,31 +47,13 @@ pub(crate) struct MacOSEmulation {
     notify_repeat_task: Arc<Notify>,
 }
 
-struct ButtonState {
+/// Maps an evdev button code to the CGEventType used for drag events.
-    left: bool,
+fn drag_event_type(button: u32) -> CGEventType {
-    right: bool,
+    match button {
-    center: bool,
+        BTN_LEFT => CGEventType::LeftMouseDragged,
-}
+        BTN_RIGHT => CGEventType::RightMouseDragged,
-
+        // middle, back, forward, and any other button all use OtherMouseDragged
-impl Index<CGMouseButton> for ButtonState {
+        _ => CGEventType::OtherMouseDragged,
-    type Output = bool;
-
-    fn index(&self, index: CGMouseButton) -> &Self::Output {
-        match index {
-            CGMouseButton::Left => &self.left,
-            CGMouseButton::Right => &self.right,
-            CGMouseButton::Center => &self.center,
-        }
-    }
-}
-
-impl IndexMut<CGMouseButton> for ButtonState {
-    fn index_mut(&mut self, index: CGMouseButton) -> &mut Self::Output {
-        match index {
-            CGMouseButton::Left => &mut self.left,
-            CGMouseButton::Right => &mut self.right,
-            CGMouseButton::Center => &mut self.center,
-        }
     }
 }
 
@@ -78,14 +63,9 @@ impl MacOSEmulation {
     pub(crate) fn new() -> Result<Self, MacOSEmulationCreationError> {
         let event_source = CGEventSource::new(CGEventSourceStateID::CombinedSessionState)
             .map_err(|_| MacOSEmulationCreationError::EventSourceCreation)?;
-        let button_state = ButtonState {
-            left: false,
-            right: false,
-            center: false,
-        };
         Ok(Self {
             event_source,
-            button_state,
+            pressed_buttons: HashSet::new(),
             previous_button: None,
             previous_button_click: None,
             button_click_state: 0,
@@ -261,14 +241,14 @@ impl Emulation for MacOSEmulation {
                         mouse_location.x = new_mouse_x;
                         mouse_location.y = new_mouse_y;
 
-                        let mut event_type = CGEventType::MouseMoved;
+                        // If any button is held, emit a drag event for it;
-                        if self.button_state.left {
+                        // otherwise emit a normal mouse-moved event.
-                            event_type = CGEventType::LeftMouseDragged
+                        let event_type = self
-                        } else if self.button_state.right {
+                            .pressed_buttons
-                            event_type = CGEventType::RightMouseDragged
+                            .iter()
-                        } else if self.button_state.center {
+                            .next()
-                            event_type = CGEventType::OtherMouseDragged
+                            .map(|&btn| drag_event_type(btn))
-                        };
+                            .unwrap_or(CGEventType::MouseMoved);
                         let event = match CGEvent::new_mouse_event(
                             self.event_source.clone(),
                             event_type,
@@ -290,6 +270,12 @@ impl Emulation for MacOSEmulation {
                         button,
                         state,
                     } => {
+                        // button number for OtherMouse events (3 = back, 4 = forward, etc.)
+                        let cg_button_number: Option<i64> = match button {
+                            BTN_BACK => Some(3),
+                            BTN_FORWARD => Some(4),
+                            _ => None,
+                        };
                         let (event_type, mouse_button) = match (button, state) {
                             (BTN_LEFT, 1) => (CGEventType::LeftMouseDown, CGMouseButton::Left),
                             (BTN_LEFT, 0) => (CGEventType::LeftMouseUp, CGMouseButton::Left),
@@ -297,17 +283,29 @@ impl Emulation for MacOSEmulation {
                             (BTN_RIGHT, 0) => (CGEventType::RightMouseUp, CGMouseButton::Right),
                             (BTN_MIDDLE, 1) => (CGEventType::OtherMouseDown, CGMouseButton::Center),
                             (BTN_MIDDLE, 0) => (CGEventType::OtherMouseUp, CGMouseButton::Center),
+                            (BTN_BACK, 1) | (BTN_FORWARD, 1) => {
+                                (CGEventType::OtherMouseDown, CGMouseButton::Center)
+                            }
+                            (BTN_BACK, 0) | (BTN_FORWARD, 0) => {
+                                (CGEventType::OtherMouseUp, CGMouseButton::Center)
+                            }
                             _ => {
                                 log::warn!("invalid button event: {button},{state}");
                                 return Ok(());
                             }
                         };
-                        // store button state
+                        // store button state using the evdev button code so
-                        self.button_state[mouse_button] = state == 1;
+                        // back, forward, and middle are tracked independently
-
-                        // update previous button state
                         if state == 1 {
-                            if self.previous_button.is_some_and(|b| b.eq(&mouse_button))
+                            self.pressed_buttons.insert(button);
+                        } else {
+                            self.pressed_buttons.remove(&button);
+                        }
+
+                        // update double-click tracking using the evdev button
+                        // code so that back/forward don't alias with middle
+                        if state == 1 {
+                            if self.previous_button == Some(button)
                                 && self
                                     .previous_button_click
                                     .is_some_and(|i| i.elapsed() < DOUBLE_CLICK_INTERVAL)
@@ -316,7 +314,7 @@ impl Emulation for MacOSEmulation {
                             } else {
                                 self.button_click_state = 1;
                             }
-                            self.previous_button = Some(mouse_button);
+                            self.previous_button = Some(button);
                             self.previous_button_click = Some(Instant::now());
                         }
 
@@ -338,6 +336,13 @@ impl Emulation for MacOSEmulation {
                             EventField::MOUSE_EVENT_CLICK_STATE,
                             self.button_click_state,
                         );
+                        // Set the button number for extra buttons (back=3, forward=4)
+                        if let Some(btn_num) = cg_button_number {
+                            event.set_integer_value_field(
+                                EventField::MOUSE_EVENT_BUTTON_NUMBER,
+                                btn_num,
+                            );
+                        }
                         event.post(CGEventTapLocation::HID);
                     }
                     PointerEvent::Axis {
@@ -416,7 +421,10 @@ impl Emulation for MacOSEmulation {
                             return Ok(());
                         }
                     };
-                    update_modifiers(&self.modifier_state, key, state);
+                    let is_modifier = update_modifiers(&self.modifier_state, key, state);
+                    if is_modifier {
+                        modifier_event(self.event_source.clone(), self.modifier_state.get());
+                    }
                     match state {
                         // pressed
                         1 => self.spawn_repeat_task(code).await,
@@ -445,21 +453,6 @@ impl Emulation for MacOSEmulation {
     async fn terminate(&mut self) {}
 }
 
-trait ButtonEq {
-    fn eq(&self, other: &Self) -> bool;
-}
-
-impl ButtonEq for CGMouseButton {
-    fn eq(&self, other: &Self) -> bool {
-        matches!(
-            (self, other),
-            (CGMouseButton::Left, CGMouseButton::Left)
-                | (CGMouseButton::Right, CGMouseButton::Right)
-                | (CGMouseButton::Center, CGMouseButton::Center)
-        )
-    }
-}
-
 fn update_modifiers(modifiers: &Cell<XMods>, key: u32, state: u8) -> bool {
     if let Ok(key) = scancode::Linux::try_from(key) {
         let mask = match key {