DevTools: NetworkPanel: reenable clicking on "expand timeline" triangles.

Source/devtools/front_end/ui/DataGrid.js

Index: Source/devtools/front_end/ui/DataGrid.js
diff --git a/Source/devtools/front_end/ui/DataGrid.js b/Source/devtools/front_end/ui/DataGrid.js
index e8dee0dfd5a0a3fa61dd35944983ca0d72c515bf..3d26267e00eb46ef8eade50b16dc7aa77aa8c250 100644
--- a/Source/devtools/front_end/ui/DataGrid.js
+++ b/Source/devtools/front_end/ui/DataGrid.js
@@ -52,7 +52,7 @@ WebInspector.DataGrid = function(columnsArray, editCallback, deleteCallback, ref
     /** @type {!Element} */
     this._dataTable = this._scrollContainer.createChild("table", "data");
 
-    this._dataTable.addEventListener("mousedown", this._mouseDownInDataTable.bind(this), true);
+    this._dataTable.addEventListener("mousedown", this._mouseDownInDataTable.bind(this));
     this._dataTable.addEventListener("click", this._clickInDataTable.bind(this), true);
 
     this._dataTable.addEventListener("contextmenu", this._contextMenuInDataTable.bind(this), true);