--- a/browser/components/downloads/DownloadsCommon.jsm
+++ b/browser/components/downloads/DownloadsCommon.jsm
@@ -720,17 +720,17 @@ DownloadsDataCtor.prototype = {
     // download terminates on a Desktop browser, it becomes a history download,
     // for which the end time is stored differently, as a Places annotation.
     download.endTime = Date.now();
 
     this.oldDownloadStates.set(download,
                                DownloadsCommon.stateOfDownload(download));
 
     for (let view of this._views) {
-      view.onDownloadAdded(download, true);
+      view.onDownloadAdded(download);
     }
   },
 
   onDownloadChanged(download) {
     let oldState = this.oldDownloadStates.get(download);
     let newState = DownloadsCommon.stateOfDownload(download);
     this.oldDownloadStates.set(download, newState);
 
@@ -835,21 +835,20 @@ DownloadsDataCtor.prototype = {
    *
    * @param aView
    *        DownloadsView object to be initialized.
    */
   _updateView(aView) {
     // Indicate to the view that a batch loading operation is in progress.
     aView.onDataLoadStarting();
 
-    // Sort backwards by start time, ensuring that the most recent
-    // downloads are added first regardless of their state.
-    let downloadsArray = [...this.downloads];
-    downloadsArray.sort((a, b) => b.startTime - a.startTime);
-    downloadsArray.forEach(download => aView.onDownloadAdded(download, false));
+    // This iterates downloads in the same order as they were originally added.
+    for (let download of this.downloads) {
+      aView.onDownloadAdded(download);
+    }
 
     // Notify the view that all data is available.
     aView.onDataLoadCompleted();
   },
 
   // Notifications sent to the most recent browser window only
 
   /**
@@ -1009,26 +1008,20 @@ const DownloadsViewPrototype = {
   },
 
   /**
    * Called when a new download data item is available, either during the
    * asynchronous data load or when a new download is started.
    *
    * @param download
    *        Download object that was just added.
-   * @param newest
-   *        When true, indicates that this item is the most recent and should be
-   *        added in the topmost position.  This happens when a new download is
-   *        started.  When false, indicates that the item is the least recent
-   *        with regard to the items that have been already added. The latter
-   *        generally happens during the asynchronous data load.
    *
    * @note Subclasses should override this.
    */
-  onDownloadAdded(download, newest) {
+  onDownloadAdded(download) {
     throw Components.results.NS_ERROR_NOT_IMPLEMENTED;
   },
 
   /**
    * Called when the overall state of a Download has changed. In particular,
    * this is called only once when the download succeeds or is blocked
    * permanently, and is never called if only the current progress changed.
    *
@@ -1121,17 +1114,17 @@ DownloadsIndicatorDataCtor.prototype = {
 
   // Callback functions from DownloadsData
 
   onDataLoadCompleted() {
     DownloadsViewPrototype.onDataLoadCompleted.call(this);
     this._updateViews();
   },
 
-  onDownloadAdded(download, newest) {
+  onDownloadAdded(download) {
     this._itemCount++;
     this._updateViews();
   },
 
   onDownloadStateChanged(download) {
     if (!download.succeeded && download.error && download.error.reputationCheckVerdict) {
       switch (download.error.reputationCheckVerdict) {
         case Downloads.Error.BLOCK_VERDICT_UNCOMMON: // fall-through
@@ -1356,23 +1349,18 @@ DownloadsSummaryData.prototype = {
   // DownloadsViewPrototype for more information on what these functions
   // are used for.
 
   onDataLoadCompleted() {
     DownloadsViewPrototype.onDataLoadCompleted.call(this);
     this._updateViews();
   },
 
-  onDownloadAdded(download, newest) {
-    if (newest) {
-      this._downloads.unshift(download);
-    } else {
-      this._downloads.push(download);
-    }
-
+  onDownloadAdded(download) {
+    this._downloads.unshift(download);
     this._updateViews();
   },
 
   onDownloadStateChanged() {
     // Since the state of a download changed, reset the estimated time left.
     this._lastRawTimeLeft = -1;
     this._lastTimeLeft = -1;
   },

--- a/browser/components/downloads/content/allDownloadsViewOverlay.js
+++ b/browser/components/downloads/content/allDownloadsViewOverlay.js
@@ -605,17 +605,17 @@ DownloadsPlacesView.prototype = {
    *     alongside the other session downloads. If we don't, then we go ahead
    *     and create a new element for the download.
    *
    * @param [optional] sessionDownload
    *        A Download object, or null for history downloads.
    * @param [optional] aPlacesNode
    *        The Places node for a history download, or null for session downloads.
    * @param [optional] aNewest
-   *        @see onDownloadAdded. Ignored for history downloads.
+   *        Whether the download should be added at the top of the list.
    * @param [optional] aDocumentFragment
    *        To speed up the appending of multiple elements to the end of the
    *        list which are coming in a single batch (i.e. invalidateContainer),
    *        a document fragment may be passed to which the new elements would
    *        be appended. It's the caller's job to ensure the fragment is merged
    *        to the richlistbox at the end.
    */
   _addDownloadData(sessionDownload, aPlacesNode, aNewest = false,
@@ -1095,18 +1095,18 @@ DownloadsPlacesView.prototype = {
     }
   },
 
   onDataLoadStarting() {},
   onDataLoadCompleted() {
     this._ensureInitialSelection();
   },
 
-  onDownloadAdded(download, newest) {
-    this._addDownloadData(download, null, newest);
+  onDownloadAdded(download) {
+    this._addDownloadData(download, null, true);
   },
 
   onDownloadStateChanged(download) {
     this._viewItemsForDownloads.get(download).onStateChanged();
   },
 
   onDownloadChanged(download) {
     this._viewItemsForDownloads.get(download).onChanged();

--- a/browser/components/downloads/content/downloads.js
+++ b/browser/components/downloads/content/downloads.js
@@ -762,43 +762,27 @@ const DownloadsView = {
   },
 
   /**
    * Called when a new download data item is available, either during the
    * asynchronous data load or when a new download is started.
    *
    * @param aDownload
    *        Download object that was just added.
-   * @param aNewest
-   *        When true, indicates that this item is the most recent and should be
-   *        added in the topmost position.  This happens when a new download is
-   *        started.  When false, indicates that the item is the least recent
-   *        and should be appended.  The latter generally happens during the
-   *        asynchronous data load.
    */
-  onDownloadAdded(download, aNewest) {
-    DownloadsCommon.log("A new download data item was added - aNewest =",
-                        aNewest);
+  onDownloadAdded(download) {
+    DownloadsCommon.log("A new download data item was added");
+
+    this._downloads.unshift(download);
 
-    if (aNewest) {
-      this._downloads.unshift(download);
-    } else {
-      this._downloads.push(download);
-    }
-
-    let itemsNowOverflow = this._downloads.length > this.kItemCountLimit;
-    if (aNewest || !itemsNowOverflow) {
-      // The newly added item is visible in the panel and we must add the
-      // corresponding element.  This is either because it is the first item, or
-      // because it was added at the bottom but the list still doesn't overflow.
-      this._addViewItem(download, aNewest);
-    }
-    if (aNewest && itemsNowOverflow) {
-      // If the list overflows, remove the last item from the panel to make room
-      // for the new one that we just added at the top.
+    // The newly added item is visible in the panel and we must add the
+    // corresponding element. If the list overflows, remove the last item from
+    // the panel to make room for the new one that we just added at the top.
+    this._addViewItem(download, true);
+    if (this._downloads.length > this.kItemCountLimit) {
       this._removeViewItem(this._downloads[this.kItemCountLimit]);
     }
 
     // For better performance during batch loads, don't update the count for
     // every item, because the interface won't be visible until load finishes.
     if (!this.loading) {
       this._itemCountChanged();
     }