The user is requested to point to the corners of a rectangle defining the region to be checked. Simply clicking will cause checking of the objects under the pointer. Holding and dragging will cause checking of all objects which overlap the ghost-drawn rectangle, when the button is released. If the user presses and holds without moving the pointer for a brief period, the ghost-drawn rectangle corner will be attached to the pointer, and pressing a second time will complete the operation. Instead of a mouse button press, pressing Enter will cause the entire area of the current cell to be checked. All objects in the current cell and its subcells which overlap the specified region are checked. Unlike the Check In Foreground command, errors are not marked on-screen. The spawned process can be stopped or killed using the job control functionality of the user's shell. There can be multiple spawned processes executing concurrently.
Under Windows, this works by executing a batch-mode Xic process in the background. However, the entire cell is always checked, any rectangle specification is ignored.