--- a/browser/base/content/browser-sidebar.js
+++ b/browser/base/content/browser-sidebar.js
@@ -253,29 +253,16 @@ var SidebarUI = {
     return this._title.value;
   },
 
   set title(value) {
     this._title.value = value;
   },
 
   /**
-   * Internal helper to show/hide the box and splitter elements.
-   *
-   * @param {bool} visible
-   */
-  _setVisibility(visible) {
-    this._box.hidden = !visible;
-    this._splitter.hidden = !visible;
-    if (visible) {
-      this.setPosition();
-    }
-  },
-
-  /**
    * Toggle the visibility of the sidebar. If the sidebar is hidden or is open
    * with a different commandID, then the sidebar will be opened using the
    * specified commandID. Otherwise the sidebar will be hidden.
    *
    * @param {string} commandID ID of the xul:broadcaster element to use.
    * @return {Promise}
    */
   toggle(commandID = this.currentID) {
@@ -322,17 +309,18 @@ var SidebarUI = {
       for (let broadcaster of broadcasters) {
         if (broadcaster != sidebarBroadcaster) {
           broadcaster.removeAttribute("checked");
         } else {
           sidebarBroadcaster.setAttribute("checked", "true");
         }
       }
 
-      this._setVisibility(true);
+      this._box.hidden = this._splitter.hidden = false;
+      this.setPosition();
 
       this.hideSwitcherPanel();
 
       this._box.setAttribute("sidebarcommand", sidebarBroadcaster.id);
       this.lastOpenedId = sidebarBroadcaster.id;
 
       let title = sidebarBroadcaster.getAttribute("sidebartitle") ||
                   sidebarBroadcaster.getAttribute("label");
@@ -396,17 +384,17 @@ var SidebarUI = {
     // until about:blank has loaded (which does not happen as long as the
     // element is hidden).
     this.browser.setAttribute("src", "about:blank");
     this.browser.docShell.createAboutBlankContentViewer(null);
 
     sidebarBroadcaster.removeAttribute("checked");
     this._box.setAttribute("sidebarcommand", "");
     this._title.value = "";
-    this._setVisibility(false);
+    this._box.hidden = this._splitter.hidden = true;
 
     let selBrowser = gBrowser.selectedBrowser;
     selBrowser.focus();
     selBrowser.messageManager.sendAsyncMessage("Sidebar:VisibilityChange",
       {commandID, isOpen: false}
     );
     BrowserUITelemetry.countSidebarEvent(commandID, "hide");
   },