diff --git a/packages/node_modules/@node-red/editor-client/src/js/ui/common/typedInput.js b/packages/node_modules/@node-red/editor-client/src/js/ui/common/typedInput.js
index 332f41fa9..e53372a52 100644
--- a/packages/node_modules/@node-red/editor-client/src/js/ui/common/typedInput.js
+++ b/packages/node_modules/@node-red/editor-client/src/js/ui/common/typedInput.js
@@ -344,6 +344,16 @@
                 that.element.val(that.value());
                 that.element.trigger('change',that.propertyType,that.value());
             });
+            this.input.on('keyup', function(evt) {
+                that.validate();
+                that.element.val(that.value());
+                that.element.trigger('keyup',evt);
+            });
+            this.input.on('paste', function(evt) {
+                that.validate();
+                that.element.val(that.value());
+                that.element.trigger('paste',evt);
+            });
             this.input.on('keydown', function(evt) {
                 if (evt.keyCode >= 37 && evt.keyCode <= 40) {
                     evt.stopPropagation();
diff --git a/packages/node_modules/@node-red/nodes/core/function/10-function.html b/packages/node_modules/@node-red/nodes/core/function/10-function.html
index 5b0e8da44..27eb588b9 100644
--- a/packages/node_modules/@node-red/nodes/core/function/10-function.html
+++ b/packages/node_modules/@node-red/nodes/core/function/10-function.html
@@ -23,6 +23,11 @@
             border-left: none;
             border-top: none;
             border-right: none;
+            padding-top: 2px;
+            padding-bottom: 2px;
+            margin-top: 4px;
+            margin-bottom: 2px;
+            height: 26px;
         }
 
         .node-libs-entry > span > i {
@@ -89,6 +94,25 @@
 
 (function() {
 
+    var invalidModuleVNames = [
+        'console',
+        'util',
+        'Buffer',
+        'Date',
+        'RED',
+        'node',
+        '__node__',
+        'context',
+        'flow',
+        'global',
+        'env',
+        'setTimeout',
+        'clearTimeout',
+        'setInterval',
+        'clearInterval',
+        'promisify'
+    ]
+
     var knownFunctionNodes = {};
     RED.events.on("nodes:add", function(n) {
         if (n.type === "function") {
@@ -193,6 +217,16 @@
                     width: "120px",
                     "margin-left": "5px"
                 }).appendTo(row0).val(opt.var);
+                var vnameWarning = $('<span style="display:inline-block; width: 16px;"><i class="fa fa-warning"></i></span>').appendTo(row0);
+                RED.popover.tooltip(vnameWarning.find("i"),function() {
+                    var val = fvar.val();
+                    if (invalidModuleVNames.indexOf(val) !== -1) {
+                        return RED._("node-red:function.error.moduleNameReserved",{name:val})
+                    } else {
+                        return RED._("node-red:function.error.moduleNameError",{name:val})
+                    }
+                })
+
                 $('<code> = require(</code>').appendTo(row0);
                 var fmodule = $("<input/>", {
                     class: "node-input-libs-val",
@@ -210,29 +244,33 @@
 
                 $('<code>)</code>').appendTo(row0);
 
-                var warning = $('<span style="display:inline-block; width: 16px;"><i class="fa fa-warning"></i></span>').appendTo(row0);
-                RED.popover.tooltip(warning.find("i"),function() {
+                var moduleWarning = $('<span style="display:inline-block; width: 16px;"><i class="fa fa-warning"></i></span>').appendTo(row0);
+                RED.popover.tooltip(moduleWarning.find("i"),function() {
                     var val = fmodule.typedInput("type");
                     if (val === "_custom_") {
                         val = fmodule.val();
                     }
+                    var errors = [];
+
                     if (!RED.utils.checkModuleAllowed(val,null,installAllowList,installDenyList)) {
-                        return "Module not allowed"
+                        return RED._("node-red:function.error.moduleNotAllowed",{module:val});
                     } else {
-                        return "Module not installed: "+missingModuleReasons[val]
+                        return RED._("node-red:function.error.moduleLoadError",{module:val,error:missingModuleReasons[val]});
                     }
                 })
 
-                fvar.on("change", function (e) {
+                fvar.on("change keyup paste", function (e) {
                     var v = $(this).val().trim();
-                    if (v === "" || / /.test(v)) {
+                    if (v === "" || / /.test(v) || invalidModuleVNames.indexOf(v) !== -1) {
                         fvar.addClass("input-error");
+                        vnameWarning.addClass("input-error");
                     } else {
                         fvar.removeClass("input-error");
+                        vnameWarning.removeClass("input-error");
                     }
                 });
 
-                fmodule.on("change", function (e) {
+                fmodule.on("change keyup paste", function (e) {
                     var val = $(this).typedInput("type");
                     if (val === "_custom_") {
                         val = $(this).val();
@@ -243,18 +281,18 @@
 
                     if (RED.utils.checkModuleAllowed(val,null,installAllowList,installDenyList) && (missingModules.indexOf(val) === -1)) {
                         fmodule.removeClass("input-error");
-                        warning.removeClass("input-error");
+                        moduleWarning.removeClass("input-error");
                     } else {
                         fmodule.addClass("input-error");
-                        warning.addClass("input-error");
+                        moduleWarning.addClass("input-error");
                     }
                 });
                 if (RED.utils.checkModuleAllowed(opt.module,null,installAllowList,installDenyList) && (missingModules.indexOf(opt.module) === -1)) {
                     fmodule.removeClass("input-error");
-                    warning.removeClass("input-error");
+                    moduleWarning.removeClass("input-error");
                 } else {
                     fmodule.addClass("input-error");
-                    warning.addClass("input-error");
+                    moduleWarning.addClass("input-error");
                 }
                 if (opt.var) {
                     fvar.trigger("change");
@@ -293,6 +331,9 @@
                     if (missingModules.indexOf(m.module) > -1) {
                         return false;
                     }
+                    if (invalidModuleVNames.indexOf(m.var) !== -1){
+                        return false;
+                    }
                 }
                 return true;
             }}
@@ -325,15 +366,15 @@
 
             tabs.addTab({
                 id: "func-tab-init",
-                label: "On Start", //that._("function.label.initialize")
+                label: that._("function.label.initialize")
             });
             tabs.addTab({
                 id: "func-tab-body",
-                label: "On Message"//that._("function.label.function")
+                label: that._("function.label.function")
             });
             tabs.addTab({
                 id: "func-tab-finalize",
-                label: "On Stop"//that._("function.label.finalize")
+                label: that._("function.label.finalize")
             });
 
             tabs.activateTab("func-tab-body");
diff --git a/packages/node_modules/@node-red/nodes/core/function/10-function.js b/packages/node_modules/@node-red/nodes/core/function/10-function.js
index b9fae8626..d6abde563 100644
--- a/packages/node_modules/@node-red/nodes/core/function/10-function.js
+++ b/packages/node_modules/@node-red/nodes/core/function/10-function.js
@@ -273,6 +273,37 @@ module.exports = function(RED) {
             sandbox.promisify = util.promisify;
         }
 
+        if (node.hasOwnProperty("libs")) {
+            let moduleErrors = false;
+            var modules = node.libs;
+            modules.forEach(module => {
+                var vname = module.hasOwnProperty("var") ? module.var : null;
+                if (vname && (vname !== "")) {
+                    if (sandbox.hasOwnProperty(vname) || vname === 'node') {
+                        node.error(RED._("function.error.moduleNameError",{name:vname}))
+                        moduleErrors = true;
+                        return;
+                    }
+                    sandbox[vname] = null;
+                    try {
+                        var spec = module.module;
+                        if (spec && (spec !== "")) {
+                            var lib = RED.require(module.module);
+                            sandbox[vname] = lib;
+                        }
+                    } catch (e) {
+                        //TODO: NLS error message
+                        node.error(RED._("function.error.moduleLoadError",{module:module.spec, error:e.toString()}))
+                        moduleErrors = true;
+                    }
+                }
+            });
+            if (moduleErrors) {
+                throw new Error("Function node failed to load external modules");
+            }
+        }
+
+
         const RESOLVING = 0;
         const RESOLVED = 1;
         const ERROR = 2;
@@ -289,26 +320,6 @@ module.exports = function(RED) {
             }
         });
 
-        if (node.hasOwnProperty("libs")) {
-            var modules = node.libs;
-            modules.forEach(module => {
-                var vname = module.hasOwnProperty("var") ? module.var : null;
-                if (vname && (vname !== "")) {
-                    sandbox[vname] = null;
-                    try {
-                        var spec = module.module;
-                        if (spec && (spec !== "")) {
-                            var lib = RED.require(module.module);
-                            sandbox[vname] = lib;
-                        }
-                    }
-                    catch (e) {
-                        console.log(e);
-                        node.warn("failed to load library: "+ module.spec);
-                    }
-                }
-            });
-        }
         var context = vm.createContext(sandbox);
         try {
             var iniScript = null;
diff --git a/packages/node_modules/@node-red/nodes/locales/en-US/messages.json b/packages/node_modules/@node-red/nodes/locales/en-US/messages.json
index 20180f33d..5dc17f76d 100755
--- a/packages/node_modules/@node-red/nodes/locales/en-US/messages.json
+++ b/packages/node_modules/@node-red/nodes/locales/en-US/messages.json
@@ -209,9 +209,9 @@
     "function": {
         "function": "",
         "label": {
-            "function": "Function",
-            "initialize": "Setup",
-            "finalize": "Close",
+            "function": "On Message",
+            "initialize": "On Start",
+            "finalize": "On Stop",
             "outputs": "Outputs",
             "require": "Require"
         },
@@ -224,6 +224,10 @@
             "module": "module"
         },
         "error": {
+            "moduleNotAllowed": "Module __module__ not allowed",
+            "moduleLoadError": "Failed to load module __module__: __error__",
+            "moduleNameError": "Invalid module variable name: __name__",
+            "moduleNameReserved": "Reserved variable name: __name__",
             "inputListener":"Cannot add listener to 'input' event within Function",
             "non-message-returned":"Function tried to send a message of type __type__"
         }
diff --git a/test/nodes/core/function/10-function_spec.js b/test/nodes/core/function/10-function_spec.js
index 95bca5fb4..7139c0e75 100644
--- a/test/nodes/core/function/10-function_spec.js
+++ b/test/nodes/core/function/10-function_spec.js
@@ -1438,7 +1438,6 @@ describe('function node', function() {
                     }
                 },20);
             }).catch(err => done(err));
-
         })
         it('should require the OS module', function(done) {
             var flow = [
@@ -1459,9 +1458,18 @@ describe('function node', function() {
                 });
                 n1.receive({payload:"foo",topic: "bar"});
             }).catch(err => done(err));
-
         })
-
+        it('should fail if module variable name clashes with sandbox builtin', function(done) {
+            var flow = [
+                {id:"n1",type:"function",wires:[["n2"]],func:"msg.payload = os.type(); return msg;", "libs": [{var:"flow", module:"os"}]},
+                {id:"n2", type:"helper"}
+            ];
+            helper.load(functionNode, flow, function() {
+                var n1 = helper.getNode("n1");
+                should.not.exist(n1);
+                done();
+            }).catch(err => done(err));
+        })
     })
 
 
diff --git a/test/unit/@node-red/registry/lib/externalModules_spec.js b/test/unit/@node-red/registry/lib/externalModules_spec.js
index 17f3cc41d..1cd274561 100644
--- a/test/unit/@node-red/registry/lib/externalModules_spec.js
+++ b/test/unit/@node-red/registry/lib/externalModules_spec.js
@@ -94,7 +94,7 @@ describe("externalModules api", function() {
         it("installs missing modules", async function() {
             externalModules.init({userDir: homeDir});
             externalModules.register("function", "libs");
-            fs.existsSync(path.join(homeDir,"externalModuels")).should.be.false();
+            fs.existsSync(path.join(homeDir,"externalModules")).should.be.false();
             await externalModules.checkFlowDependencies([
                 {type: "function", libs:[{module: "foo"}]}
             ])