Layers are only meant to backup the focus window

radio/src/thirdparty/libopenui/src/layer.h

@@ -37,20 +37,12 @@ class Layer
 
     static void push(Window * window)
     {
-      if (window->getLvObj()->parent != nullptr) {
-        TRACE("Layers must have lvgl parent to be null");
-      }
 
       if (!stack.empty()) {
         Layer & parentLayer = stack.back();
         parentLayer.focus = Window::getFocus();
       }
 
-      // layers are screens in lvgl
-      lv_obj_set_parent(canvas, window->getLvObj());
-      lv_obj_move_background(canvas);
-      lv_scr_load(window->getLvObj());
-      lv_obj_invalidate(canvas);
 
       stack.emplace_back(Layer(window));
 
@@ -67,9 +59,6 @@ class Layer
       if (stack.back().main == window) {
         stack.pop_back();
         const auto & back = stack.back();
-        lv_obj_set_parent(canvas, back.main->getLvObj());
-        lv_obj_move_background(canvas);
-        lv_scr_load(back.main->getLvObj());  // load the screen.
         if (back.focus) {
           back.focus->setFocus(SET_FOCUS_DEFAULT);
         }
@@ -78,8 +67,6 @@ class Layer
         // TODO it would be better to do it in reverse order
         for (auto it = stack.begin(); it != stack.end(); it++) {
           if (it->main == window) {
-            lv_obj_set_parent(canvas, it->main->getLvObj());
-            lv_scr_load(it->main->getLvObj());
             stack.erase(it);
             break;
           }

radio/src/thirdparty/libopenui/src/mainwindow.cpp

@@ -24,17 +24,21 @@
 #include "touch.h"
 #endif
 
-MainWindow * MainWindow::_instance = nullptr;
-
-LvglWidgetFactory mainWindowFactory = LvglWidgetFactory([] (lv_obj_t *parent) {
-  return lv_obj_create(nullptr);
-});
-
-
 #if defined(HARDWARE_TOUCH)
 TouchState touchState;
 #endif
 
+static LvglWidgetFactory mainWindowFactory = { lv_obj_create, nullptr };
+
+MainWindow * MainWindow::_instance = nullptr;
+
+MainWindow::MainWindow() :
+    Window(nullptr, {0, 0, LCD_W, LCD_H}, 0, 0, &mainWindowFactory),
+    invalidatedRect(rect)
+{
+  Layer::push(this);
+}
+
 void MainWindow::emptyTrash()
 {
   for (auto window: trash) {

radio/src/thirdparty/libopenui/src/mainwindow.h

@@ -23,18 +23,11 @@
 #include "layer.h"
 #include "bitmapbuffer.h"
 
-extern LvglWidgetFactory mainWindowFactory;
-
 class MainWindow: public Window
 {
   protected:
     // singleton
-    MainWindow():
-      Window(nullptr, {0, 0, LCD_W, LCD_H}, 0, 0, &mainWindowFactory),
-      invalidatedRect(rect)
-    {
-      Layer::push(this);
-    }
+    MainWindow();
 
   public:
     ~MainWindow() override