# Objective
- Currently when you attempt to change the cursor_grab_mode it caches
the new value whether the cursor grab succeeded or failed. This change
handles the Result being returned by set_cursor_grab and changes the
cursor_grab_mode back to the cached version in case of an Error.
- Creates a way to handle #16237 and #16238
## Solution
- I changed the signature of winit_windows attempt_grab to return the
Result<(), ExternalError> that winit set_cursor_grab returns. The system
that calls attempt_grab now checks if there's an error returned, and if
there is it sets the grab_mode back to the cached version (similar to
what hit_test does a few lines down).
## Testing
- I tested using this system that previously would not correctly lock
the mouse on Ubuntu/x11
```
pub fn lock_mouse(mut primary_window: Query<&mut Window, With<PrimaryWindow>>) {
let window = &mut primary_window.single_mut();
if window.focused {
window.cursor_options.grab_mode = CursorGrabMode::Confined;
} else {
window.cursor_options.grab_mode = CursorGrabMode::None;
}
}
```
- I only tested on Ubuntu with x11
1e3ecbefdb