fix #1749

gui/kivy/uix/screens.py

@@ -164,7 +164,8 @@ class HistoryScreen(CScreen):
             ri.icon = icon
             ri.date = date_time
             ri.message = message
-            ri.value = value
+            ri.value = value if value is not None else 0
+            ri.value_known = value is not None
             ri.quote_text = quote_text
             ri.confirmations = conf
             ri.tx_hash = tx

gui/kivy/uix/ui_screens/history.kv

@@ -20,7 +20,8 @@
     icon: 'atlas://gui/kivy/theming/light/important'
     message: ''
     value: 0
-    amount: app.format_amount(self.value, True) if self.value is not None else '--'
+    value_known: True
+    amount: app.format_amount(self.value, True) if self.value_known else '--'
     amount_color: '#FF6657' if self.value < 0 else '#2EA442'
     confirmations: 0
     date: ''