Build system changed to Cmake, ORM changed to QxORM, Qt6 compatibility.

core/defaultformhandler.cpp

@@ -1,7 +1,7 @@
 #include "defaultformhandler.h"
 
 #include <QApplication>
-#include <QDesktopWidget>
+#include <QScreen>
 #include <QRect>
 
 DefaultFormHandler::DefaultFormHandler()
@@ -19,7 +19,12 @@ void DefaultFormHandler::showForm(IForm *formWidget)
     formWidget->onShow();
     m_dialog->setForm(formWidget);
     m_dialog->setModal(true);
-    m_dialog->move(QApplication::desktop()->screen()->rect().center() - m_dialog->rect().center());
+    auto screen = m_dialog->screen();
+
+    if (screen) {
+        m_dialog->move(screen->availableGeometry().center() - m_dialog->rect().center());
+    }
+
     m_dialog->show();
 }