diff --git a/packages/node_modules/@node-red/editor-client/src/js/nodes.js b/packages/node_modules/@node-red/editor-client/src/js/nodes.js
index a27e491f8..ee7e7413f 100644
--- a/packages/node_modules/@node-red/editor-client/src/js/nodes.js
+++ b/packages/node_modules/@node-red/editor-client/src/js/nodes.js
@@ -611,7 +611,9 @@ RED.nodes = (function() {
             node.y = n.y;
             node.w = n.w;
             node.h = n.h;
-            node.nodes = node.nodes.map(function(n) { return n.id });
+            // In 1.1.0, we have seen an instance of this array containing `undefined`
+            // Until we know how that can happen, add a filter here to remove them
+            node.nodes = node.nodes.filter(function(n) { return !!n }).map(function(n) { return n.id });
         }
         if (n._def.category != "config") {
             node.x = n.x;
@@ -991,7 +993,7 @@ RED.nodes = (function() {
         var workspace_map = {};
         var new_subflows = [];
         var subflow_map = {};
-        var subflow_blacklist = {};
+        var subflow_denylist = {};
         var node_map = {};
         var new_nodes = [];
         var new_links = [];
@@ -1024,7 +1026,7 @@ RED.nodes = (function() {
             } else if (n.type === "subflow") {
                 var matchingSubflow = checkForMatchingSubflow(n,nodeZmap[n.id]);
                 if (matchingSubflow) {
-                    subflow_blacklist[n.id] = matchingSubflow;
+                    subflow_denylist[n.id] = matchingSubflow;
                 } else {
                     subflow_map[n.id] = n;
                     if (createNewIds) {
@@ -1075,7 +1077,7 @@ RED.nodes = (function() {
                 var existingConfigNode = null;
                 if (createNewIds) {
                     if (n.z) {
-                        if (subflow_blacklist[n.z]) {
+                        if (subflow_denylist[n.z]) {
                             continue;
                         } else if (subflow_map[n.z]) {
                             n.z = subflow_map[n.z].id;
@@ -1182,7 +1184,7 @@ RED.nodes = (function() {
                         node.g = n.g;
                     }
                     if (createNewIds) {
-                        if (subflow_blacklist[n.z]) {
+                        if (subflow_denylist[n.z]) {
                             continue;
                         } else if (subflow_map[node.z]) {
                             node.z = subflow_map[node.z].id;
@@ -1229,7 +1231,7 @@ RED.nodes = (function() {
                         node._config.y = node.y;
                     } else if (n.type.substring(0,7) === "subflow") {
                         var parentId = n.type.split(":")[1];
-                        var subflow = subflow_blacklist[parentId]||subflow_map[parentId]||getSubflow(parentId);
+                        var subflow = subflow_denylist[parentId]||subflow_map[parentId]||getSubflow(parentId);
                         if (createNewIds) {
                             parentId = subflow.id;
                             node.type = "subflow:"+parentId;
@@ -1439,6 +1441,7 @@ RED.nodes = (function() {
             n.nodes = n.nodes.map(function(id) {
                 return node_map[id];
             })
+            // Just in case the group references a node that doesn't exist for some reason
             n.nodes = n.nodes.filter(function(v) { return !!v});
             if (!n.g) {
                 groupDepthMap[n.id] = 0;
diff --git a/packages/node_modules/@node-red/editor-client/src/js/ui/subflow.js b/packages/node_modules/@node-red/editor-client/src/js/ui/subflow.js
index 88a42063f..2909d1133 100644
--- a/packages/node_modules/@node-red/editor-client/src/js/ui/subflow.js
+++ b/packages/node_modules/@node-red/editor-client/src/js/ui/subflow.js
@@ -454,8 +454,10 @@ RED.subflow = (function() {
     }
 
     function removeSubflow(id) {
+        // TODO:  A lot of this logic is common with RED.nodes.removeWorkspace
         var removedNodes = [];
         var removedLinks = [];
+        var removedGroups = [];
 
         var activeSubflow = RED.nodes.subflow(id);
 
@@ -472,7 +474,9 @@ RED.subflow = (function() {
                 removedNodes.push(n);
             }
         });
-
+        RED.nodes.groups(id).forEach(function(n) {
+            removedGroups.push(n);
+        })
         var removedConfigNodes = [];
         for (var i=0;i<removedNodes.length;i++) {
             var removedEntities = RED.nodes.remove(removedNodes[i].id);
@@ -482,6 +486,18 @@ RED.subflow = (function() {
         // TODO: this whole delete logic should be in RED.nodes.removeSubflow..
         removedNodes = removedNodes.concat(removedConfigNodes);
 
+        removedGroups = RED.nodes.groups(id).filter(function(g) { return !g.g; });
+        for (i=0;i<removedGroups.length;i++) {
+            removedGroups[i].nodes.forEach(function(n) {
+                if (n.type === "group") {
+                    removedGroups.push(n);
+                }
+            });
+        }
+        // Now remove them in the reverse order
+        for (i=removedGroups.length-1; i>=0; i--) {
+            RED.nodes.removeGroup(removedGroups[i]);
+        }
         RED.nodes.removeSubflow(activeSubflow);
         RED.workspaces.remove(activeSubflow);
         RED.nodes.dirty(true);
@@ -490,6 +506,7 @@ RED.subflow = (function() {
         return {
             nodes:removedNodes,
             links:removedLinks,
+            groups: removedGroups,
             subflows: [activeSubflow]
         }
     }