Qt: adapt receive_lightning_help text

electrum/gui/qt/main_window.py

@@ -1184,7 +1184,7 @@ class ElectrumWindow(QMainWindow, MessageBoxMixin, Logger):
         self.receive_address_e = ButtonsTextEdit()
         self.receive_URI_e = ButtonsTextEdit()
         self.receive_lightning_e = ButtonsTextEdit()
-        self.receive_lightning_help = WWLabel('You do not have the capacity to receive this amount using Lightning')
+        self.receive_lightning_help = WWLabel('')
         self.receive_lightning_help.setVisible(False)
         #self.receive_URI_e.setFocusPolicy(Qt.ClickFocus)
 
@@ -1274,6 +1274,14 @@ class ElectrumWindow(QMainWindow, MessageBoxMixin, Logger):
         URI = req.get_bip21_URI(lightning=bip21_lightning)
         lnaddr = lnaddr or ''
         icon_name = "lightning.png" if can_receive_lightning else "lightning_disconnected.png"
+        if not lnaddr:
+            if can_receive_lightning:
+                ln_help = _('No lightning invoice')
+            else:
+                ln_help = _('You do not have the capacity to receive this amount using Lightning')
+        else:
+            ln_help = ''
+
         self.receive_tabs.setTabIcon(2, read_QIcon(icon_name))
         # encode lightning invoices as uppercase so QR encoding can use
         # alphanumeric mode; resulting in smaller QR codes
@@ -1283,6 +1291,7 @@ class ElectrumWindow(QMainWindow, MessageBoxMixin, Logger):
         self.receive_URI_e.setText(URI)
         self.receive_URI_qr.setData(URI)
         self.receive_lightning_e.setText(lnaddr)  # TODO maybe prepend "lightning:" ??
+        self.receive_lightning_help.setText(ln_help)
         self.receive_lightning_qr.setData(lnaddr_qr)
         # macOS hack (similar to #4777)
         self.receive_lightning_e.repaint()