public void setKeyboardSelectionHandler(CellPreviewEvent.Handler<T> keyboardSelectionReg) {
        // Remove the old manager.
        if (this.keyboardSelectionReg != null) {
            this.keyboardSelectionReg.removeHandler();
            this.keyboardSelectionReg = null;
        }

        // Add the new manager.
        if (keyboardSelectionReg != null) {
            this.keyboardSelectionReg = addCellPreviewHandler(keyboardSelectionReg);
        }
    }
Set the handler that handles keyboard selection/navigation.
stroom-core-client-widget/src/main/java/com/google/gwt/user/cellview/client/AbstractHasData.java