function _closeAll(paneId) {
        _forEachPaneOrPanes(paneId, function (pane) {
            var closedList = pane.getViewList();
            closedList.forEach(function (file) {
                _removeFileFromMRU(pane.id, file);
            });

            pane._reset();
            exports.trigger("workingSetRemoveList", closedList, pane.id);
        });
    }
Closes all files in the specified pane or panes
@param {!string} paneId - id of the pane in which to open the document
This function does not fail if the file is not open