Major crashing bug fixed, program returned to normal operations

minimal_crash_test.py

@@ -0,0 +1,62 @@
+"""
+Minimal, standalone crash test - completely independent of the Order
+Manager app. Run this directly:
+
+    python minimal_crash_test.py
+
+Click "Open Dialog", then close it (X button or Cancel). If this
+crashes the same way (exit code -1073740791 / 0xC0000409), the issue
+is in your PyQt6 install/environment itself, not in anything specific
+to the Order Manager codebase - every fix attempt there has been
+chasing the wrong thing.
+"""
+import sys
+from PyQt6.QtWidgets import (
+    QApplication,
+    QMainWindow,
+    QPushButton,
+    QDialog,
+    QVBoxLayout,
+    QLineEdit,
+    QLabel,
+    QDialogButtonBox,
+)
+
+
+class MinimalDialog(QDialog):
+    def __init__(self, parent=None):
+        super().__init__(parent)
+        self.setWindowTitle("Minimal Test Dialog")
+        layout = QVBoxLayout(self)
+        layout.addWidget(QLabel("Just a label and a text field."))
+        layout.addWidget(QLineEdit("1.00"))
+
+        button_box = QDialogButtonBox()
+        button_box.addButton("OK", QDialogButtonBox.ButtonRole.AcceptRole)
+        button_box.addButton(QDialogButtonBox.StandardButton.Cancel)
+        button_box.accepted.connect(self.accept)
+        button_box.rejected.connect(self.reject)
+        layout.addWidget(button_box)
+
+
+class MainWindow(QMainWindow):
+    def __init__(self):
+        super().__init__()
+        self.setWindowTitle("Minimal Crash Test")
+        self.resize(300, 100)
+        button = QPushButton("Open Dialog")
+        button.clicked.connect(self.open_dialog)
+        self.setCentralWidget(button)
+
+    def open_dialog(self):
+        print("about to open dialog", flush=True)
+        dialog = MinimalDialog(self)
+        result = dialog.exec()
+        print(f"dialog closed, result={result}", flush=True)
+
+
+if __name__ == "__main__":
+    app = QApplication(sys.argv)
+    window = MainWindow()
+    window.show()
+    sys.exit(app.exec())