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+# Desktop: unread count in the window title
+
+## What
+
+The desktop app's main window title changes from `SimpleX` to `SimpleX [N]`
+when there are unread messages the user would be notified about; the suffix
+disappears when `N` is 0.
+
+The window title shows in the window's own title bar, in Windows and
+Linux taskbars and window switchers that show window titles, and in macOS
+Mission Control (the macOS Dock and Cmd-Tab show the app name).
+
+Scope: the main window only. File-chooser dialogs and the developer Terminal
+window keep their own titles.
+
+## Why
+
+Desktop already has OS notifications (they disappear after seconds) and, for
+users who chose "minimize to tray", the tray icon (a dot; the count is in a
+hover tooltip). Neither gives a glanceable count to a user working in another
+window.
+
+## Counting rules
+
+`N` = active-profile count + other-profiles count.
+
+**Active profile** — sum over its loaded chats, by each chat's `enableNtfs`:
+
+| `enableNtfs` | counted |
+|---|---|
+| `All` | `chatStats.unreadCount` |
+| `Mentions` | `chatStats.unreadMentions`, at most `chatStats.unreadCount` |
+| `None` | 0 |
+
+**Other profiles** — each non-active profile that is not hidden and not
+profile-muted (`showNtfs`) contributes its `UserInfo.unreadCount` (the core
+computes it with chat mute applied; the app keeps it up to date for chats that
+notify).
+
+Not counted: hidden non-active profiles, profile-muted non-active profiles,
+fully muted chats, and the `unreadChat` flag (chats marked unread with no
+unread messages). Like the chat list, the active profile's part covers only
+the loaded chats (up to 5000), and while the app is switched to a connected
+mobile the profiles are that mobile's.
+
+The mentions count is capped by the unread count because the app lowers
+`unreadCount` but not `unreadMentions` in `decreaseCounterInPrimaryContext`
+(e.g. when an unread mention is deleted); without the cap the title would
+keep counting a mention after the chat has no unread messages, until the
+chat is opened or the chats are reloaded (with other unread messages left,
+the stale mention still counts, as the chat list's @ badge shows it). The model drift itself is a separate bug.
+
+Unread messages in member support chats ("Chat with admins") are not
+counted for the active profile (the chat list's unread badge excludes
+them; the row shows a flag icon instead), except
+messages arriving while the user is a pending member, which are counted
+until the chat is opened or the chats are reloaded. By the code, other profiles'
+`UserInfo.unreadCount` includes them (the core's per-profile count has no
+support-scope filter), so the total could change when switching
+profiles; not verified by a test.
+
+## Change
+
+One file, `DesktopApp.kt`: the `Window` composable's `title` (was
+`"SimpleX"`) is derived from the count in a `derivedStateOf` over
+`ChatModel.chats` and `ChatModel.users`. Compose passes it to the AWT
+`Frame` title; no native code. The title notifies observers only when the
+total changes.
+
+The two parts of the count come from different sources because the active
+profile's `users[active].unreadCount` goes up on every unread message
+in a loaded chat (outside support chats, unless the user is a pending
+member) regardless of chat mute; the per-chat walk applies each chat's mode.
+
+While switching profiles, `users` is updated before the new profile's chats
+are loaded, so for that moment the old profile's chats are counted as active
+and (unless it is hidden or muted) again as another profile, and the new
+profile's are not counted.
+
+## Privacy
+
+The title is visible in the window's title bar and readable by other
+software (any X11 client, other processes on Windows, screen-share window
+pickers, activity trackers), and it is shown
+while SimpleX Lock has locked the app. The count, not the content, is
+exposed; whether that needs a setting or should be hidden while locked is a
+maintainer decision.
+
+## Out of scope
+
+- macOS Dock badge — separate API.
+- Tray icon / tooltip logic — left unchanged, so the tooltip can show a
+  different number for the active profile.
+- A setting to turn it off.
+- Per-platform format variants — `SimpleX [N]` everywhere.