control panel: highlight first tab on opening settings / set as active (#90)

thanks to @ErdoesiT for the fix!

src/Playback/UIComponents/ControlPanel/ControlPanel.ts

@@ -143,6 +143,7 @@ export class ControlPanel extends AUIController<IPlaybackParametersListener> imp
             self.hideAndClear();
             //self.eventListener.onClose();
         };
+        tabBar.activateTab(0);
         tabBar.listen("MDCTabBar:activated", function(event: CustomEvent): void {
             switch (event.detail.index) {
                 case 0: