make question dialog child of SettingsDialog

electrum/gui/qt/settings_dialog.py

@@ -121,7 +121,7 @@ class SettingsDialog(QDialog, QtEventListener):
                         _("Are you sure you want to disable trampoline?"),
                         _("Without this option, Electrum will need to sync with the Lightning network on every start."),
                         _("This may impact the reliability of your payments."),
-                ])):
+                ]), parent=self):
                     trampoline_cb.setCheckState(Qt.CheckState.Checked)
                     return
             self.config.LIGHTNING_USE_GOSSIP = not use_trampoline