AMBARI-4088. UI doesn't select all hosts on Assign Slaves step sometimes. (alexantonenko)

ambari-web/app/styles/apps.less

@@ -534,3 +534,23 @@
 }
 
 /*Big modal window end*/
+#step6{
+  .spinner-overlay{
+    z-index: 100;
+    position: absolute;
+    margin-top: 169px;
+    width: 758px;
+    height: 444px;
+    background-color: #808080;
+    opacity:0.2;
+  }
+  .spinner {
+    position: absolute;
+    z-index: 100;
+    margin-top: 369px;
+    margin-left: 362px;
+    display: inline-block;
+    width: 36px;
+    opacity: 1;
+  }
+}

ambari-web/app/templates/wizard/step6.hbs

@@ -17,6 +17,8 @@
 }}
 
 <div id="step6">
+  <div {{bindAttr class=":spinner-overlay controller.isLoaded:hidden"}}></div>
+  <i {{bindAttr class=":icon-spin :spinner controller.isLoaded:hidden"}}></i>
   <h2>{{view.title}}</h2>
   <div class="alert alert-info">{{{view.label}}}</div>
   {{#if errorMessage}}