QmlDesigner: Activate created timeline

Change-Id: I2b8ba374ed463c9062035a9b5b0d2e8209819c4d
Reviewed-by: Knud Dollereder <knud.dollereder@qt.io>
Reviewed-by: Thomas Hartmann <thomas.hartmann@qt.io>

src/plugins/qmldesigner/components/timelineeditor/timelineview.cpp

@@ -378,6 +378,7 @@ void TimelineView::addNewTimelineDialog()
 {
     auto timeline = addNewTimeline();
     addAnimation(timeline);
+    activateTimeline(timeline);
     openSettingsDialog();
 }