function _getPaneIdForPath(fullPath) {
        // Search all working sets and pull off the first one
        var info = findInAllWorkingSets(fullPath).shift();

        // Look for a view that has not been added to a working set
        if (!info) {
            _.forEach(_panes, function (pane) {
                if (pane.getCurrentlyViewedPath() === fullPath) {
                    info = {paneId: pane.id};
                    return false;
                }
            });
        }

        if (!info) {
            return null;
        }

        return info.paneId;
    }
@private
Retrieves pane id where the specified file has been opened. Used to ensure that a file
 is open in only one pane so this will change once support for multiple views is added
The result includes panes with a temporary view of the file not just working set instances
@param {!string} fullPath - full path of the file to search for
@return {?string} pane id where the file has been opened or null if it wasn't found