docs(linux): note that touchpad tap-to-click is not captured

evdev sees a physical clickpad press (a real BTN_LEFT) but not a tap: libinput
synthesises tap-to-click above the kernel device and never writes it back, so
there is nothing at the evdev layer the helper reads. Document the limitation
for users under "Mouse clicks on Wayland", and at the device_reports_left_button
site where a touchpad passes the BTN_LEFT check yet silently drops taps.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: 2 people

electron/native/pipewire-capture/src/input.rs

@@ -79,6 +79,13 @@ pub fn spawn_readers(sender: &Sender<Message>) -> ClickCapture {
     }
 }
 
+/// A touchpad advertises `BTN_LEFT` for a physical clickpad press, so it passes
+/// this check and its node is opened — but tap-to-click never arrives here.
+/// libinput consumes the raw `BTN_TOUCH`/`ABS_MT_*` stream and synthesises the
+/// button for its own clients without writing `BTN_LEFT` back to the kernel
+/// device, so a tap is invisible at the evdev layer we read. The consequence is
+/// documented for users under "Mouse clicks on Wayland" in the installation docs:
+/// on a touchpad only hard presses are captured, taps are not.
 fn device_reports_left_button(device: &Device) -> bool {
     device
         .supported_keys()

website/docs/installation.md

@@ -123,6 +123,8 @@ Log out and back in for the new group to take effect. Nothing breaks without it
 
 The scope is deliberately narrow: only the left mouse button (`BTN_LEFT`) is ever read, never keystrokes. To turn the reader off entirely even where the permission exists, set `OPENSCREEN_DISABLE_CLICK_CAPTURE=1` in the environment OpenScreen is launched from.
 
+**Touchpads:** only a physical click — pressing the pad down until it depresses — is recorded. **Tap-to-click is not**, because your compositor's input stack (libinput) synthesises those taps for its own use and never writes them back to the kernel device that OpenScreen reads, so there is nothing at the evdev layer to see. A mouse, or a touchpad with tap-to-click turned off, records every click.
+
 ## Platform differences
 
 The editing tools are the same everywhere — zooms, backgrounds, crop/trim/speed, annotations, transcription, captions, and projects. Every export format works on every platform; what differs is **capture**, and how fast MP4 encodes on Linux: