diff --git a/devtools/client/inspector/inspector.js b/devtools/client/inspector/inspector.js
index 79dcb331a8e98..096f1680fba99 100644
--- a/devtools/client/inspector/inspector.js
+++ b/devtools/client/inspector/inspector.js
@@ -380,7 +380,7 @@ Inspector.prototype = {
       "visible";
 
     // Setup the sidebar panels.
-    await this.setupSidebar();
+    this.setupSidebar();
 
     await onMarkupLoaded;
     this.isReady = true;
@@ -813,7 +813,7 @@ Inspector.prototype = {
   async onSidebarToggle() {
     this.is3PaneModeEnabled = !this.is3PaneModeEnabled;
     await this.setupToolbar();
-    await this.addRuleView({ skipQueue: true });
+    this.addRuleView({ skipQueue: true });
   },
 
   /**
@@ -884,7 +884,7 @@ Inspector.prototype = {
    * @params {String} defaultTab
    *         Thie id of the default tab for the sidebar.
    */
-  async addRuleView({ defaultTab = "ruleview", skipQueue = false } = {}) {
+  addRuleView({ defaultTab = "ruleview", skipQueue = false } = {}) {
     const ruleViewSidebar = this.sidebarSplitBoxRef.current.startPanelContainer;
 
     if (this.is3PaneModeEnabled) {
@@ -898,7 +898,7 @@ Inspector.prototype = {
       // Force the rule view panel creation by calling getPanel
       this.getPanel("ruleview");
 
-      await this.sidebar.removeTab("ruleview");
+      this.sidebar.removeTab("ruleview");
 
       this.ruleViewSideBar.addExistingTab(
         "ruleview",
@@ -932,7 +932,7 @@ Inspector.prototype = {
       });
 
       this.ruleViewSideBar.hide();
-      await this.ruleViewSideBar.removeTab("ruleview");
+      this.ruleViewSideBar.removeTab("ruleview");
 
       if (skipQueue) {
         this.sidebar.addExistingTab(
@@ -1040,7 +1040,7 @@ Inspector.prototype = {
   /**
    * Build the sidebar.
    */
-  async setupSidebar() {
+  setupSidebar() {
     const sidebar = this.panelDoc.getElementById("inspector-sidebar");
     const options = {
       showAllTabsMenu: true,
@@ -1072,7 +1072,7 @@ Inspector.prototype = {
 
     // Append all side panels
 
-    await this.addRuleView({ defaultTab });
+    this.addRuleView({ defaultTab });
 
     // Inspector sidebar panels in order of appearance.
     const sidebarPanels = [
diff --git a/devtools/client/inspector/toolsidebar.js b/devtools/client/inspector/toolsidebar.js
index e59b046aae361..d8b0ed7ad2810 100644
--- a/devtools/client/inspector/toolsidebar.js
+++ b/devtools/client/inspector/toolsidebar.js
@@ -153,7 +153,7 @@ ToolSidebar.prototype = {
    * @param {String} tabPanelId Optional. If provided, this ID will be used
    * instead of the tabId to retrieve and remove the corresponding <tabpanel>
    */
-  async removeTab(tabId, tabPanelId) {
+  removeTab(tabId, tabPanelId) {
     this._tabbar.removeTab(tabId);
 
     this.emit("tab-unregistered", tabId);