qt: fix some widget parenting issues

If you force-show a widget (e.g. `w.setVisible(True)`) before parenting it,
a small window will flash (appear and disappear) for a fraction of second,
which is a bit irritating.

electrum/gui/qt/main_window.py

@@ -1028,9 +1028,10 @@ class ElectrumWindow(QMainWindow, MessageBoxMixin, Logger):
         self.history_model.set_view(self.history_list)
         l.searchable_list = l
         toolbar = l.create_toolbar(self.config)
+        tab = self.create_list_tab(l, toolbar)
         toolbar_shown = bool(self.config.get('show_toolbar_history', False))
         l.show_toolbar(toolbar_shown)
-        return self.create_list_tab(l, toolbar)
+        return tab
 
     def show_address(self, addr):
         from . import address_dialog
@@ -2032,9 +2033,10 @@ class ElectrumWindow(QMainWindow, MessageBoxMixin, Logger):
         from .address_list import AddressList
         self.address_list = l = AddressList(self)
         toolbar = l.create_toolbar(self.config)
+        tab =  self.create_list_tab(l, toolbar)
         toolbar_shown = bool(self.config.get('show_toolbar_addresses', False))
         l.show_toolbar(toolbar_shown)
-        return self.create_list_tab(l, toolbar)
+        return tab
 
     def create_utxo_tab(self):
         from .utxo_list import UTXOList
@@ -2247,8 +2249,8 @@ class ElectrumWindow(QMainWindow, MessageBoxMixin, Logger):
         self.seed_button = StatusBarButton(read_QIcon("seed.png"), _("Seed"), self.show_seed_dialog)
         sb.addPermanentWidget(self.seed_button)
         self.lightning_button = StatusBarButton(read_QIcon("lightning.png"), _("Lightning Network"), self.gui_object.show_lightning_dialog)
-        self.update_lightning_icon()
         sb.addPermanentWidget(self.lightning_button)
+        self.update_lightning_icon()
         self.status_button = None
         if self.network:
             self.status_button = StatusBarButton(read_QIcon("status_disconnected.png"), _("Network"), self.gui_object.show_network_dialog)

electrum/gui/qt/password_dialog.py

@@ -124,7 +124,8 @@ class PasswordLayout(object):
         self.encrypt_cb = QCheckBox(_('Encrypt wallet file'))
         self.encrypt_cb.setEnabled(False)
         grid.addWidget(self.encrypt_cb, 4, 0, 1, 2)
-        self.encrypt_cb.setVisible(kind != PW_PASSPHRASE)
+        if kind == PW_PASSPHRASE:
+            self.encrypt_cb.setVisible(False)
 
         def enable_OK():
             ok = self.new_pw.text() == self.conf_pw.text()