fix(controller): pick up macOS presses while mpv is in front (#321)

docs-site/usage.md

@@ -195,6 +195,8 @@ The media timing review and duplicate card (field grouping) dialogs have their o
 
 On controllers that report the W3C standard layout, the default quit button lands on `L2` instead of `Select`, and the default pause button on `Start` instead of `L3`. The default right-stick popup jump does nothing on these controllers; click **Learn** on **Popup Jump (Stick)** and move the right stick up or down to set it. Remap anything else with `Alt+C`, which names buttons according to the layout your controller reports. All options are in [Configuration](/configuration#controller-support).
 
+On macOS, a controller only reaches the app in front. When mpv is in front, a controller button brings the overlay to the front and then runs that button's action. With more than one controller connected, that first press only brings the overlay to the front; press the button again to run its action. Stick movements only work once the overlay is in front. Buttons pressed while another app is in front are left alone.
+
 ## Development profiles
 
 `--dev` and `--debug` use a separate `SubMiner-dev` profile. They do not read or modify dictionaries and configuration from the installed app unless `SUBMINER_USE_PRODUCTION_PROFILE=1` is explicitly set. See [Development](/development#run-locally).