diff --git a/pcbnew/dialogs/dialog_copper_zones.cpp b/pcbnew/dialogs/dialog_copper_zones.cpp
index 760fa8d6cd..02d0948c78 100644
--- a/pcbnew/dialogs/dialog_copper_zones.cpp
+++ b/pcbnew/dialogs/dialog_copper_zones.cpp
@@ -186,6 +186,8 @@ DIALOG_COPPER_ZONE::DIALOG_COPPER_ZONE( PCB_BASE_FRAME* aParent, ZONE_SETTINGS*
     m_settings.SetupLayersList( m_layers, m_Parent, true );
 
     m_settingsExported = false;
+    m_currentlySelectedNetcode = INVALID_NET_CODE;
+    m_maxNetCode = INVALID_NET_CODE;
 
     m_netSortingByPadCount = true;      // false = alphabetic sort, true = pad count sort