qml: expose RbF in config/preferences

electrum/gui/qml/components/Preferences.qml

@@ -233,6 +233,16 @@ Pane {
                             }
                         }
 
+                        Switch {
+                            id: useRbf
+                            text: qsTr('Use Replace-By-Fee')
+                            Layout.columnSpan: 2
+                            onCheckedChanged: {
+                                if (activeFocus)
+                                    Config.useRbf = checked
+                            }
+                        }
+
                     }
 
                 }
@@ -287,6 +297,7 @@ Pane {
         spendUnconfirmed.checked = Config.spendUnconfirmed
         lnRoutingType.currentIndex = Config.useGossip ? 0 : 1
         useFallbackAddress.checked = Config.useFallbackAddress
+        useRbf.checked = Config.useRbf
 
         var plugins = AppController.plugins
         for (var i=0; i<plugins.length; i++) {

electrum/gui/qml/components/WalletMainView.qml

@@ -241,7 +241,7 @@ Item {
             title: qsTr('Confirm Payment')
             finalizer: TxFinalizer {
                 wallet: Daemon.currentWallet
-                canRbf: true
+                canRbf: Config.useRbf
             }
             onClosed: destroy()
         }

electrum/gui/qml/qeconfig.py

@@ -130,6 +130,16 @@ class QEConfig(AuthMixin, QObject):
         self.config.set_key('bolt11_fallback', use_fallback)
         self.useFallbackAddressChanged.emit()
 
+    useRbfChanged = pyqtSignal()
+    @pyqtProperty(bool, notify=useRbfChanged)
+    def useRbf(self):
+        return self.config.get('use_rbf', True)
+
+    @useRbf.setter
+    def useRbf(self, useRbf):
+        self.config.set_key('use_rbf', useRbf)
+        self.useRbfChanged.emit()
+
     @pyqtSlot('qint64', result=str)
     @pyqtSlot('qint64', bool, result=str)
     @pyqtSlot(QEAmount, result=str)