rem: if (this._tree.view.rowCount == 0) 
add: if (this._tree.view.rowCount == 0) { this._removeButton.disabled = true; this._editButton.disabled = true; 
context:   onSelectionChanged: function ()  {    if (this._tree.view.rowCount == 0)      return;          var selection = this._tree.view.selection;     var selected = selection.count;    this._removeButton.disabled = selected == 0;    this._editButton.disabled = selected != 1;    var stringKey = selected > 1 ? "removeButtonMultiple" : "removeButtonSingle";    this._removeButton.label = this._bundle.getString(stringKey);        var canRemove = true;    var canEdit = true;        var rangeCount = selection.getRangeCount();    var min = { }, max = { };    var setLastSelected = false;    for (var i = 0; i < rangeCount; ++i) {      selection.getRangeAt(i, min, max);            for (var j = min.value; j <= max.value; ++j) {        if (!setLastSelected) {          // Set the last selected index to the first item in the selection          this._tree.setAttribute("lastSelected", j);          setLastSelected = true;        }        var item = this._view.getItemAtIndex(j);        if (item &&             (!item.editable || item.handleMode == FILEACTION_OPEN_INTERNALLY))          canEdit = false;                if (item &&             (!item.editable || item.handleMode == FILEACTION_OPEN_INTERNALLY ||             item.handledOnlyByPlugin))          canRemove = false;      }    }        if (!canRemove)      this._removeButton.disabled = true;    if (!canEdit)      this._editButton.disabled = true;  },
meta: 10234	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/10234/6a6d7ddb144434cd65e5f86bdef38f8897c3c06e/downloadactions.js/clean/browser/components/preferences/downloadactions.js