function _documentSelectionFocusChange() {
        var curFullPath = MainViewManager.getCurrentlyViewedPath(MainViewManager.ACTIVE_PANE);
        if (curFullPath && _hasFileSelectionFocus()) {
            actionCreator.setSelected(curFullPath, true);
        } else {
            actionCreator.setSelected(null);
        }
        _fileViewControllerChange();
    }
@private

Handler for changes in document selection.