function _onWorkingSetRemove(event, removedFile) {
        // There's one case where an editor should be disposed even though the current document
        // didn't change: removing a document from the working set (via the "X" button). (This may
        // also cover the case where the document WAS current, if the editor-swap happens before the
        // removal from the working set.
        var doc = DocumentManager.getOpenDocumentForPath(removedFile.fullPath);
        if (doc) {
            _destroyEditorIfUnneeded(doc);
        }
        // else, file was listed in working set but never shown in the editor - ignore
    }
Handles removals from DocumentManager's working set list