move slider when new frame is added

src/app_layout.cpp

@@ -1347,12 +1347,13 @@ void App::initLayout()
                         frame_text->set_text(str);
                     }
                 };
-            }
-            if (auto btn_add = timeline->find<NodeButtonCustom>("btn-add"))
-            {
-                btn_add->on_click = [this] (Node*) {
-                    layers->add_layer(true, true);
-                };
+                if (auto btn_add = timeline->find<NodeButtonCustom>("btn-add"))
+                {
+                    btn_add->on_click = [this, slider] (Node*) {
+                        layers->add_layer(true, true);
+                        slider->set_value(1.f, true);
+                    };
+                }
             }
         }