diff --git a/common/dialogs/panel_setup_netclasses.cpp b/common/dialogs/panel_setup_netclasses.cpp
index f9b2cd1670..73f3bd55a7 100644
--- a/common/dialogs/panel_setup_netclasses.cpp
+++ b/common/dialogs/panel_setup_netclasses.cpp
@@ -442,14 +442,11 @@ bool PANEL_SETUP_NETCLASSES::TransferDataFromWindow()
         wxString netclass = m_assignmentGrid->GetCellValue( row, 1 );
 
         m_netSettings->m_NetClassPatternAssignments.push_back(
-                {
-                    std::make_unique<EDA_COMBINED_MATCHER>( pattern, CTX_NETCLASS ),
-                    netclass
-                } );
-
-        m_netSettings->m_NetClassPatternAssignmentCache.clear();
+                { std::make_unique<EDA_COMBINED_MATCHER>( pattern, CTX_NETCLASS ), netclass } );
     }
 
+    m_netSettings->m_NetClassPatternAssignmentCache.clear();
+
     return true;
 }
 
diff --git a/eeschema/connection_graph.cpp b/eeschema/connection_graph.cpp
index 3bbea06880..e4ab119936 100644
--- a/eeschema/connection_graph.cpp
+++ b/eeschema/connection_graph.cpp
@@ -2375,9 +2375,6 @@ void CONNECTION_GRAPH::buildConnectionGraph( std::function<void( SCH_ITEM* )>* a
                     }
                 }
 
-                if( netclass.IsEmpty() )
-                    return;
-
                 if( !driverSubgraph )
                     driverSubgraph = subgraphs.front();
 
@@ -2387,7 +2384,10 @@ void CONNECTION_GRAPH::buildConnectionGraph( std::function<void( SCH_ITEM* )>* a
                 {
                     for( const auto& member : driverSubgraph->m_driver_connection->Members() )
                     {
-                        netSettings->m_NetClassLabelAssignments[ member->Name() ] = netclass;
+                        if( netclass.IsEmpty() )
+                            netSettings->m_NetClassLabelAssignments.erase( member->Name() );
+                        else
+                            netSettings->m_NetClassLabelAssignments[member->Name()] = netclass;
 
                         auto ii = m_net_name_to_subgraphs_map.find( member->Name() );
 
@@ -2396,9 +2396,17 @@ void CONNECTION_GRAPH::buildConnectionGraph( std::function<void( SCH_ITEM* )>* a
                     }
                 }
 
-                netSettings->m_NetClassLabelAssignments[ netname ] = netclass;
+                if( netclass.IsEmpty() )
+                    netSettings->m_NetClassLabelAssignments.erase( netname );
+                else
+                    netSettings->m_NetClassLabelAssignments[netname] = netclass;
 
-                if( oldAssignments[ netname ] != netclass )
+                if( oldAssignments.count( netname ) )
+                {
+                    if( oldAssignments[netname] != netclass )
+                        dirtySubgraphs( subgraphs );
+                }
+                else if( !netclass.IsEmpty() )
                     dirtySubgraphs( subgraphs );
             };