3 files changed, 20 insertions, 9 deletions
diff --git a/devtools/client/netmonitor/netmonitor-controller.js b/devtools/client/netmonitor/netmonitor-controller.js
index 939b6e4f5e..39bee85707 100644
--- a/devtools/client/netmonitor/netmonitor-controller.js
+++ b/devtools/client/netmonitor/netmonitor-controller.js
@@ -407,6 +407,9 @@ TargetEventsHandler.prototype = {
         if (!Services.prefs.getBoolPref("devtools.webconsole.persistlog")) {
           NetMonitorView.RequestsMenu.reset();
           NetMonitorView.Sidebar.toggle(false);
+        } else {
+          // If the log is persistent, just clear some informations.
+          NetMonitorView.RequestsMenu.resetNotPersistent();
         }
         // Switch to the default network traffic inspector view.
         if (NetMonitorController.getCurrentActivity() == ACTIVITY_TYPE.NONE) {
diff --git a/devtools/client/netmonitor/requests-menu-view.js b/devtools/client/netmonitor/requests-menu-view.js
index c491fcb0e9..0c854d264b 100644
--- a/devtools/client/netmonitor/requests-menu-view.js
+++ b/devtools/client/netmonitor/requests-menu-view.js
@@ -275,8 +275,15 @@ RequestsMenuView.prototype = Heritage.extend(WidgetMethods, {
     this._addQueue = [];
     this._updateQueue = [];
     this._firstRequestStartedMillis = -1;
-    this._firstRequestStartedMillisInRequests = false;
     this._lastRequestEndedMillis = -1;
+    this.resetNotPersistent();
+  },
+
+  /**
+   * Reset informations that "devtools.webconsole.persistlog == true".
+   */
+  resetNotPersistent: function () {
+    this._firstRequestStartedMillisNotPersistent = -1;
   },
 
   /**
@@ -651,9 +658,7 @@ RequestsMenuView.prototype = Heritage.extend(WidgetMethods, {
       // Append a network request item to this container.
       let requestItem = this.push([menuView, id], {
         attachment: {
-          firstRequestStartedMillis: this._firstRequestStartedMillisInRequests
-                                     ? null
-                                     : this._firstRequestStartedMillis,
+          firstRequestStartedMillisNotPersistent: this._firstRequestStartedMillisNotPersistent,
           startedDeltaMillis: unixTime - this._firstRequestStartedMillis,
           startedMillis: unixTime,
           method: method,
@@ -665,8 +670,6 @@ RequestsMenuView.prototype = Heritage.extend(WidgetMethods, {
         }
       });
 
-      this._firstRequestStartedMillisInRequests = true;
-
       if (id == this._preferredItemId) {
         this.selectedItem = requestItem;
       }
@@ -1528,6 +1531,9 @@ RequestsMenuView.prototype = Heritage.extend(WidgetMethods, {
     if (this._firstRequestStartedMillis == -1) {
       this._firstRequestStartedMillis = unixTime;
     }
+    if (this._firstRequestStartedMillisNotPersistent == -1) {
+      this._firstRequestStartedMillisNotPersistent = unixTime;
+    }
   },
 
   /**
@@ -1569,7 +1575,7 @@ RequestsMenuView.prototype = Heritage.extend(WidgetMethods, {
   _ctx: null,
   _cachedWaterfallWidth: 0,
   _firstRequestStartedMillis: -1,
-  _firstRequestStartedMillisInRequests: false,
+  _firstRequestStartedMillisNotPersistent: -1,
   _lastRequestEndedMillis: -1,
   _updateQueue: [],
   _addQueue: [],
diff --git a/devtools/client/netmonitor/selectors/index.js b/devtools/client/netmonitor/selectors/index.js
index 6121887581..ba5c190948 100644
--- a/devtools/client/netmonitor/selectors/index.js
+++ b/devtools/client/netmonitor/selectors/index.js
@@ -80,8 +80,10 @@ function getDisplayedTimingMarker(state, marker) {
   }    
   let firstRequestStartedMillis = null;
   if (state.requests.items.length) {
-    firstRequestStartedMillis = state.requests.items[0]
-                                .attachment.firstRequestStartedMillis;
+    firstRequestStartedMillis = state.requests
+                                .items[state.requests.items.length - 1]
+                                .attachment
+                                .firstRequestStartedMillisNotPersistent;
   }
   if (timingMarker && firstRequestStartedMillis) {
     return timingMarker - firstRequestStartedMillis;