Notes on your screen.
Invisible on theirs.

Every time you share your screen on Zoom, Teams, or Google Meet, the video-conferencing app needs to capture what is on your display and send it to the other participants. On macOS, there are two main ways an app can do this — and understanding them explains why your regular notes window always shows up in screen share.

CGWindowList: the classic approach

The first method, and the one most screen-sharing apps have used for years, is an API called CGWindowList. When Zoom or Teams calls this API, macOS responds with a list of every window currently drawn on your display — your browser, your code editor, your Finder windows, and yes, your notes. The screen-sharing app then composites all of those windows into a single image and sends it over the wire to the other participants on the call. Every window is included by default. There is no way for an ordinary window to opt out. If it is on your screen, it is in the capture.

This is why the common workaround of "just share a single window instead of your whole screen" exists. When you share a specific application window, the screen-sharing tool only captures that one window — so other windows are excluded. But this workaround falls apart the moment you need to switch between apps during a live demo, or when you accidentally share the wrong window, or when you want to show your desktop. And some conferencing tools don’t even offer window-level sharing.

ScreenCaptureKit: the modern method

Starting with macOS 12.3, Apple introduced a new framework called ScreenCaptureKit. This is a more granular, more efficient replacement for CGWindowList-based capture. ScreenCaptureKit gives the capturing application a filter-based system: it can request specific windows, specific apps, or the entire display. It also supports excluding specific windows from capture. Newer versions of Zoom, Teams, and Meet are migrating to ScreenCaptureKit because it uses less CPU and produces better-quality video.

But here is the important part: even with ScreenCaptureKit, a regular notes window is still captured by default. Unless a window explicitly tells macOS "do not include me in any screen capture," it will appear in the stream. The conferencing app does not decide which windows to exclude — it simply asks macOS for what is on the screen, and macOS hands over everything that has not opted out.

Why your notes always show up

Apple Notes, TextEdit, Notion, Obsidian, Google Docs in a browser — none of these applications tell macOS to exclude their windows from capture. They are general-purpose tools, and their windows behave like any other window on the system. When you share your screen, they are visible to everyone on the call.

The common workarounds all have drawbacks. Sharing a single window limits your workflow. A second monitor causes visible eye movement. Sticky notes on your monitor are visible to your webcam. Your phone propped up next to your screen makes you look down. None of these are actual solutions — they are compromises.

The real solution is a window that tells macOS, at the system level, to exclude it from all screen capture. That is exactly what ShowNotes does.

macOS provides a window-level property called sharingType = .none. When an application sets this property on its window, macOS marks that window as excluded from all forms of screen capture — CGWindowList, ScreenCaptureKit, and any other capture mechanism the operating system supports. The window is still fully visible to you on your display, but as far as any screen-recording or screen-sharing tool is concerned, it does not exist.

This is not a hack or a workaround. It is a documented, Apple-supported API that exists specifically for this purpose. The most well-known application that uses it is 1Password: when you reveal a password in 1Password, the password field is displayed in a content-protected window so that if you happen to be sharing your screen, nobody on the other end sees your credentials. ShowNotes uses the same mechanism for a different purpose — keeping your presentation notes, talking points, and cue cards invisible during a live call.

What content protection means in practice

When ShowNotes is running and you start sharing your screen, your audience sees everything on your display except the ShowNotes window. In its place, they see whatever is behind it — your slides, your demo app, your browser, your desktop wallpaper. There is no black rectangle, no placeholder, no visual artifact. The window simply is not part of the captured image. It is as if you had closed ShowNotes entirely, except you have not — it is right there on your screen, with your notes visible to you.

ShowNotes also sets its window to float above other applications, so it stays in view no matter what app is in the foreground. Combined with content protection, this means your notes are always visible to you and never visible to your audience. Toggle the window on and off with a global keyboard shortcut from any app — even mid-screen-share.