Add deactivate-unfocused-windows debug flag (#1706)

* force xdg deactivation on invisable workspaces

This debug option provides a workaround for many Chromium-based chat
applications that fail to show notifications when they're active in
a workspace that's not currently visible and don't have keyboard focus

Signed-off-by: Alex Yosifov <sashomasho@gmail.com>

* fixes

---------

Signed-off-by: Alex Yosifov <sashomasho@gmail.com>
Co-authored-by: Ivan Molodetskikh <yalterz@gmail.com>

wiki/Configuration:-Debug-Options.md

@@ -28,8 +28,9 @@ debug {
     keep-laptop-panel-on-when-lid-is-closed
     disable-monitor-names
     strict-new-window-focus-policy
-    honor-xdg-activation-with-invalid-serial 
+    honor-xdg-activation-with-invalid-serial
     skip-cursor-only-updates-during-vrr
+    deactivate-unfocused-windows
 }
 
 binds {
@@ -292,6 +293,22 @@ debug {
 }
 ```
 
+### `deactivate-unfocused-windows`
+
+<sup>Since: next release</sup>
+
+Some clients (notably, Chromium- and Electron-based, like Teams or Slack) erroneously use the Activated xdg window state instead of keyboard focus for things like deciding whether to send notifications for new messages, or for picking where to show an IME popup.
+Niri keeps the Activated state on unfocused workspaces and invisible tabbed windows (to reduce unwanted animations), surfacing bugs in these applications.
+
+Set this debug flag to work around these problems.
+It will cause niri to drop the Activated state for all unfocused windows.
+
+```kdl
+debug {
+    deactivate-unfocused-windows
+}
+```
+
 ### Key Bindings
 
 These are not debug options, but rather key bindings.