[NetworkSetup] fix issue #3409 (comment)

Author: atvcaptain

lib/python/Screens/NetworkSetup.py

@@ -281,12 +281,15 @@ def dnsRefresh(refresh):
 	def createSetup(self):  # NOSONAR silence S2638
 		Setup.createSetup(self)
 		dnsList = self["config"].getList()
+		if hasattr(self, "dnsStart"):
+			del dnsList[self.dnsStart:]
 		self.dnsStart = len(dnsList)
 		items = [NoSave(ConfigIP(default=x)) for x in self.dnsServers if isinstance(x, list)] + [NoSave(ConfigText(default=x, fixed_size=False)) for x in self.dnsServers if isinstance(x, str)]
+		entry = None
 		for item, entry in enumerate(items, start=1):
 			dnsList.append(getConfigListEntry(_("Name server %d") % item, entry, _("Enter DNS (Dynamic Name Server) %d's IP address.") % item))
-		self.dnsLength = item
-		if self.entryAdded:
+		self.dnsLength = item if items else 0
+		if self.entryAdded and entry:
 			entry.default = [256, 256, 256, 256]  # This triggers a cancel confirmation for unedited new entries.
 			self.entryAdded = False
 		self["config"].setList(dnsList)