Cleaner closing

src/main/Simulator/Generated/data.mo

@@ -0,0 +1,64 @@
+within Simulator.Generated;
+
+package data
+
+  record GeneralProperties "Record to declare the variables for thermophysical properties of the compounds in the database"
+      extends Modelica.Icons.Record;
+    parameter Integer SN "Serial Number";
+    parameter String name "Compound Name";
+    parameter String CAS "CAS Number";
+    parameter Real Tc (unit="K") "Critical Temperature";
+    parameter Real Pc (unit="Pa") "Critical Pressure";
+    parameter Real Vc (unit="m3/kmol") "Critical Volume";
+    parameter Real Cc (unit="-") "Critical Compressibility Factor";
+    parameter Real Tb (unit="K") "Boiling Point Temperature";
+    parameter Real Tm (unit="K") "Melting Point Temperature";
+    parameter Real TT (unit="K") "Triple Point Temperature";
+    parameter Real TP (unit="Pa") "Triple Point Pressure";
+    parameter Real MW (unit="-") "Molecular Weight";
+    parameter Real LVB (unit="m3/kmol") "Liquid Molar Volume at Normal Boiling Point";
+    parameter Real AF (unit="-") "Acentric Factor";
+    parameter Real SP (unit="J0.5/m1.5") "Solubility Parameter";
+    parameter Real DM (unit="Coulomb.m") "Dipole Moment";
+    parameter Real SH (unit="J/kmol") "Absolute Enthalpy";
+    parameter Real IGHF (unit="J/kmol") "Standard Heat of Formation";
+    parameter Real GEF (unit="J/kmol") "Gibbs Energy of Formation";
+    parameter Real AS (unit="J/kmol/K") "Absolute Entropy";
+    parameter Real HFMP (unit="J/kmol") "Heat of Fusion at Melting Point";
+    parameter Real HOC (unit="J/kmol") "Heat of Combustion";
+    parameter Real UniquacR (unit="-") "UNIQUAC r";
+    parameter Real UniquacQ (unit="-") "UNIQUAC q";
+    parameter Real LiqDen[6] (each unit="kmol/m3") "Liquid Density Coefficients";
+    parameter Real VP[6] (each unit="Pa") "Vapor Pressure Coefficients";
+    parameter Real LiqCp[6] (each unit="J/kmol/K") "Liquid Heat Capacity Coefficients";
+    parameter Real HOV[6] (each unit="J/kmol") "Heat of Vaporization Coefficients";
+    parameter Real VapCp[6] (each unit="J/kmol/K") "Ideal Gas Heat Capacity Coefficients";
+    parameter Real LiqVis[6] (each unit="Pa s") "Liquid Viscosity Coefficients";
+    parameter Real VapVis[6] (each unit="Pa s") "Vapor Viscosity Coefficients";
+    parameter Real LiqK[6] (each unit="W/m/K") "Liquid Thermal Conductivity Coefficients";
+    parameter Real VapK[6] (each unit="W/m/K") "Vapor Thermal Conductivity Coefficients";
+    parameter Real Racketparam (unit="-") "Racket Parameter";
+    parameter Real ChaoSeadAF (unit="-") "Chao-Seader Accentric Factor";
+    parameter Real ChaoSeadSP (unit="J0.5/m1.5") "Shao-Seader Solubility Parameter";
+    parameter Real ChaoSeadLV (unit="m3/kmol") "Chao-Seader Liquid Volume";
+  end GeneralProperties;
+
+
+  record Air
+      extends Modelica.Icons.Record;
+    extends GeneralProperties(SN = 1, name = "Air", CAS = "132259-10-0", Tc = 132.45, Pc = 3774000, Vc = 0.09147, Cc = 0.313, Tb = 78.67, Tm = 59.15, TT = 59.15, TP = 5642.15, MW = 28.96, LVB = 0.0329147, AF = 0, SP = 12750, DM = 0, SH = 0.0, IGHF = 0, GEF = 0, AS = 199000, HFMP = 0, HOC = 0, LiqDen = {105, 2.6731, 0.25637, 132.51, 0.26788, 0}, VP = {101, 14.794, -599.85, 1.0009, -3.9938E-07, 2}, LiqCp = {16, 53628, 4511.1, -143.29, 1.582, -0.0051332}, HOV = {106, 7385651, 0.276676, 0.211253, -0.836764, 0.722737}, VapCp = {100, 29562.29, -7.164949, 0.0216294, -0.0000139748, 2.89195E-09}, LiqVis = {101, -72.336, 813.48, 12.687, -0.00033062, 2}, VapVis = {102, 0.000001592, 0.48975, 123.45, -829.58, 0}, LiqK = {16, -0.21199, -16.311, -0.23057, -0.0076197, 0.0000025018}, VapK = {102, 0.0003511, 0.76492, 16.071, 1084.4, 0}, Racketparam = 0.29056, UniquacR = 0, UniquacQ = 0, ChaoSeadAF = -0.00787976, ChaoSeadSP = 12749.8, ChaoSeadLV = 0.0329147);
+  end Air;
+
+
+  record Argon
+      extends Modelica.Icons.Record;
+    extends GeneralProperties(SN = 2, name = "Argon", CAS = "7440-37-1", Tc = 150.86, Pc = 4898000, Vc = 0.07457, Cc = 0.291, Tb = 87.27, Tm = 83.8039, TT = 83.8, TP = 68906.1, MW = 39.948, LVB = 0.0291, AF = -0.002, SP = 14138.3, DM = 0, SH = 0.0, IGHF = 0, GEF = 0, AS = 154732, HFMP = 1184900, HOC = 0, LiqDen = {105, 3.803, 0.286, 150.86, 0.2984, 0}, VP = {101, 44.369, -1126.1, -4.5688, 0.000062339, 2}, LiqCp = {16, 46085, -1304.5, 21.195, -0.015382, 0.000033063}, HOV = {106, 7981000, 0.099752, 0.32009, -0.11898, 0.031141}, VapCp = {16, 20786, 0, 0, 0, 0}, LiqVis = {101, -99.903, 1347.5, 17.615, -0.00032893, 2}, VapVis = {102, 0.0000010023, 0.5922, 85.563, 238.26, 0}, LiqK = {16, -0.30397, -0.82999, -0.71462, -0.00039294, -0.000012209}, VapK = {102, 0.00013095, 0.81923, -122.33, 13993, 0}, Racketparam = 0, UniquacR = 1.1074, UniquacQ = 1.068, ChaoSeadAF = -0.002, ChaoSeadSP = 14138.3, ChaoSeadLV = 0.0285865);
+  end Argon;
+
+
+  record Bromine
+      extends Modelica.Icons.Record;
+    extends GeneralProperties(SN = 3, name = "Bromine", CAS = "7726-95-6", Tc = 584.15, Pc = 1.03E+07, Vc = 0.135, Cc = 0.286, Tb = 331.9, Tm = 265.9, TT = 265.85, TP = 5853.37, MW = 159.808, LVB = 0.0514795, AF = 0.128997, SP = 23590, DM = 0, SH = 0.0, IGHF = 3.091E+07, GEF = 3140000, AS = 245350, HFMP = 1.057E+07, HOC = 0, LiqDen = {105, 2.0603, 0.28982, 584.15, 0.28948, 0}, VP = {101, 63.657, -5321.6, -6.3199, 0.0000054412, 2}, LiqCp = {16, 75351, -4.87E+07, 54033, 102.73, 0.43775}, HOV = {106, 3.8419E+07, -0.26282, 2.1808, -2.7529, 1.1823}, VapCp = {16, 35000, -410, 8.5, -0.00016, -0.00000001}, LiqVis = {101, -5.9813, 410.55, -0.30036, -0.000006936, 2}, VapVis = {102, 1.1438E-07, 0.88111, 59.595, -6723.3, 0}, LiqK = {16, -0.69183, 27.775, -0.38966, 0.00057103, -8.8462E-07}, VapK = {102, 0.0000065648, 1.4785, 4505.6, -870500, 0}, Racketparam = 0.279241, UniquacR = 1.8985, UniquacQ = 1.672, ChaoSeadAF = 0.108, ChaoSeadSP = 23591.8, ChaoSeadLV = 0.0514795);
+  end Bromine;
+
+end data;

src/main/Simulator/Generated/package.mo

@@ -0,0 +1,5 @@
+within Simulator;
+
+package Generated
+  extends Modelica.Icons.Package;
+end Generated;

src/main/python/Landing_page.py

@@ -22,6 +22,20 @@
 sys.path.insert(0, os.path.abspath(os.path.join(os.path.dirname(__file__), '..', '..', '..')))
 from src.main.ui.utils.LandingPageUI import IconPanel, GlassButton
 
+# Import the module-level globals that Graphics.py uses so we can
+# purge them before stashing the old MainApp window.
+try:
+    from python.utils.Graphics import dock_widget_lst as _dock_widget_lst, lst as _node_lst
+except Exception:
+    _dock_widget_lst = None
+    _node_lst = None
+
+# Keep old MainApp instances alive (hidden) so their C++ objects are never
+# destroyed while something might still reference them.  This prevents the
+# "wrapped C/C++ object has been deleted" crashes and the "Not responding"
+# freezes caused by asynchronous deleteLater() destruction.
+_stashed_windows = []
+
 class LandingPage(QWidget):
     def __init__(self):
         super().__init__()
@@ -41,7 +55,7 @@ def __init__(self):
         self.main_window = None
         self.init_ui()
 
-        # 🔥 Start background preload once the window is ready
+        # Start background preload once the window is ready
         QTimer.singleShot(500, self.preload_main_window)
 
     def paintEvent(self, event):
@@ -157,13 +171,33 @@ def start_simulation(self):
 
 
     def _cleanup_main_window(self):
-        """Safely schedule the old main window for deletion."""
+        """Hide the old main window and stash it so it stays alive.
+
+        We intentionally do NOT call deleteLater().  Destroying a QMainWindow
+        with dozens of child widgets, dock widgets, QThreads, and scene items
+        triggers asynchronous C++ object destruction that races with the Qt
+        event loop and causes 'Not responding' freezes or outright segfaults.
+        Keeping the old window alive but hidden is safe and costs very little
+        memory (users won't create hundreds of sessions).
+        """
         if self.main_window is not None:
+            # Clear the module-level global Graphics lists so the new
+            # MainApp starts with clean state.
+            try:
+                if _dock_widget_lst is not None:
+                    _dock_widget_lst.clear()
+                if _node_lst is not None:
+                    _node_lst.clear()
+            except Exception:
+                pass
+
             try:
                 self.main_window.hide()
-                self.main_window.deleteLater()
             except Exception:
                 pass
+
+            # Stash — prevent Python GC from collecting (and destroying) it
+            _stashed_windows.append(self.main_window)
             self.main_window = None
 
     def open_existing_project(self):
@@ -184,18 +218,8 @@ def open_existing_project(self):
             self._cleanup_main_window()
             self.main_window = MainApp()
 
-            # Preserve original closeEvent
-            orig_close = getattr(self.main_window, "closeEvent", None)
-            def _wrapped_close(event):
-                try:
-                    if orig_close is not None:
-                        orig_close(event)
-                except Exception:
-                    pass
-                if event.isAccepted():
-                    # Defer restoration so closeEvent finishes before we touch self.main_window
-                    QTimer.singleShot(0, self.restore_landing_page)
-            self.main_window.closeEvent = _wrapped_close
+            # Connect to closed signal to restore landing page
+            self.main_window.closed.connect(lambda: QTimer.singleShot(0, self.restore_landing_page))
 
             # Open project file
             self.main_window.open(file_path)
@@ -241,18 +265,8 @@ def launch_main_window(self):
             self.main_window = MainApp()
             self.main_window.new_project()  # reset all components for new project
 
-            # Wrap closeEvent to restore landing page
-            orig_close = getattr(self.main_window, "closeEvent", None)
-            def _wrapped_close(event):
-                if orig_close:
-                    try:
-                        orig_close(event)
-                    except Exception:
-                        pass
-                if event.isAccepted():
-                    # Defer restoration so closeEvent finishes before we touch self.main_window
-                    QTimer.singleShot(0, self.restore_landing_page)
-            self.main_window.closeEvent = _wrapped_close
+            # Connect to closed signal to restore landing page
+            self.main_window.closed.connect(lambda: QTimer.singleShot(0, self.restore_landing_page))
 
             # Show main window maximized
             self.main_window.showMaximized()
@@ -324,20 +338,26 @@ def fit_canvas(self):
         gv.centerOn(self.main_window.scene.itemsBoundingRect().center())
         self.reset_cursor()
 
+    def closeEvent(self, event):
+        # Explicitly quit the entire application when the landing page is closed
+        QApplication.quit()
+        event.accept()
+
     def restore_landing_page(self):
+        # Drain the entire override cursor stack left by MainApp/Graphics/Container
+        # before showing the landing page, to prevent corrupted mouse events.
+        while QApplication.overrideCursor() is not None:
+            QApplication.restoreOverrideCursor()
+
         # Safely clean up old main window using Qt event loop
         self._cleanup_main_window()
 
-        # Show landing page in full screen
-        # self.showFullScreen()  
-
         # Show landing page (windowed)
         self.show()
 
         # Make sure it is active
         self.activateWindow()
         self.raise_()
-        # QApplication.processEvents()
 
     def resizeEvent(self, event):
         # """Make sure gradient background fills screen on resize."""
@@ -391,6 +411,7 @@ def reset_cursor(self):
 
 def run():
     app = QApplication(sys.argv)
+    app.setQuitOnLastWindowClosed(False)
     window = LandingPage()
     window.show()
     sys.exit(app.exec_())

src/main/python/mainApp.py

@@ -88,6 +88,7 @@ def eventFilter(self, obj, event):
     MainApp class is responsible for all the main App Ui operations
 '''
 class MainApp(QMainWindow,ui):
+    closed = pyqtSignal()
     global compound_selected
     '''
         Initializing the application
@@ -446,20 +447,27 @@ def simulate(self, mode):
         Terminate the current running simulation
     '''
     def terminate(self):
-        os.chdir(self.container.flowsheet.root_dir)
-        if self.thrd:
+        try:
+            os.chdir(self.container.flowsheet.root_dir)
+        except Exception:
+            pass
+
+        if self.thrd and self.thrd.is_alive():
             thread_id = self.thrd.ident
-            # print('____________________Going to terminate simulation thread with Thread ID:',thread_id,'____________________')
-            # print('____________________Going to terminate the new process created for omc____________________')
-            self.container.flowsheet.process.terminate()
-            print('____________________New process created for omc is terminated.____________________')
-            res = ctypes.pythonapi.PyThreadState_SetAsyncExc(thread_id, ctypes.py_object(SystemExit)) 
+            if hasattr(self.container, 'flowsheet') and hasattr(self.container.flowsheet, 'process') and self.container.flowsheet.process:
+                try:
+                    self.container.flowsheet.process.terminate()
+                    print('____________________New process created for omc is terminated.____________________')
+                except Exception:
+                    pass
+
+            res = ctypes.pythonapi.PyThreadState_SetAsyncExc(ctypes.c_long(thread_id), ctypes.py_object(SystemExit)) 
             self.textBrowser.append("<span style=\"color:red\">["+str(self.current_time())+"]<b>Simulation Terminated.</b></span>")
             self.container.disableInterfaceforSimulation(False)
-            # print('____________________Simulation thread terminated____________________')
             if res > 1: 
-                ctypes.pythonapi.PyThreadState_SetAsyncExc(thread_id, 0) 
-                # print('Exception raise (Thread termination) failure')
+                ctypes.pythonapi.PyThreadState_SetAsyncExc(ctypes.c_long(thread_id), 0)
+
+        self.thrd = None
 
     '''
         Resets the zoom level to default scaling
@@ -626,10 +634,13 @@ def new(self):
                 if hasattr(cls, "counter"):
                     cls.counter = 1
 
-            # Clear old dock widgets
+            # Clear old dock widgets — guard against already-deleted C++ objects
             for dw in dock_widget_lst:
-                dw.hide()
-                dw.setParent(None)
+                try:
+                    dw.hide()
+                    dw.setParent(None)
+                except RuntimeError:
+                    pass  # C++ object already deleted — safe to skip
             dock_widget_lst.clear()
 
             # Reset compound selection
@@ -893,6 +904,21 @@ def _clear_selected_compounds_panel(self):
         self.selectedElementsList.clear()
         self._sel_status_label.setText("No compounds selected")
 
+    def closeEvent(self, event):
+        # Stop simulation thread if still running
+        try:
+            if self.thrd and self.thrd.is_alive():
+                self.terminate()
+        except Exception:
+            pass
+
+        # Drain any override cursors this window left on the stack
+        while QApplication.overrideCursor() is not None:
+            QApplication.restoreOverrideCursor()
+
+        event.accept()
+        self.closed.emit()
+
 from python.utils.ComponentSelectorWindow import ComponentSelectorWindow
 
 def select_compounds(self):

src/main/python/utils/Container.py

@@ -44,7 +44,7 @@ def __init__(self, msgbrowser, graphicsView):
         self.result = []
         self.graphics = Graphics(self, self.graphicsView)
         self.scene = self.graphics.get_scene()
-        print(f"[DEBUG] Scene check → container.scene id={id(self.scene)}, graphics.scene id={id(self.graphics.scene)}")
+        print(f"[DEBUG] Scene check -> container.scene id={id(self.scene)}, graphics.scene id={id(self.graphics.scene)}")
 
 
     # ----------------- Utility -----------------