fix lazy initialization of the sidebar

src/public/javascripts/widgets/side_pane_toggles.js

@@ -28,7 +28,7 @@ const TPL = `
 </div>
 `;
 
-export default class SidepaneToggles extends BasicWidget {
+export default class SidePaneToggles extends BasicWidget {
     constructor(appContext) {
         super(appContext);
 

src/public/javascripts/widgets/tab_aware_widget.js

@@ -78,6 +78,10 @@ export default class TabAwareWidget extends BasicWidget {
     }
 
     lazyLoadedListener() {
+        if (!this.tabContext) { // has not been loaded yet
+            this.tabContext = this.appContext.getActiveTabContext();
+        }
+
         this.refresh();
     }
 }