ensure fallback value is defined on value updates

src/Umbraco.Web.UI.Client/src/common/directives/components/buttons/umbbutton.directive.js

@@ -171,7 +171,7 @@ Use this directive to render an umbraco button. The directive can be used to gen
                     vm.innerState = changes.state.currentValue;
                 }
                 if (changes.state.currentValue === 'success' || changes.state.currentValue === 'error') {
-                    // set the state back to 'init' after a success or error 
+                    // set the state back to 'init' after a success or error
                     $timeout(function () {
                         vm.innerState = 'init';
                     }, 2000);
@@ -196,6 +196,13 @@ Use this directive to render an umbraco button. The directive can be used to gen
                 setButtonLabel();
             }
 
+            // watch for type changes
+            if(changes.type) {
+                if (!vm.type) {
+                    vm.type = "button";// set the default
+                }
+            }
+
         }
 
         function clickButton(event) {