GUACAMOLE-723: Avoid DOM reflow when switching connections.

guacamole/src/main/webapp/app/client/styles/keyboard.css

@@ -18,6 +18,8 @@
  */
 
 .keyboard-container {
+
+    display: none;
     text-align: center;
 
     width: 100%;
@@ -29,4 +31,9 @@
     opacity: 0.85;
 
     z-index: 1;
+
 }
+
+.keyboard-container.open {
+    display: block;
+}

guacamole/src/main/webapp/app/client/styles/text-input.css

@@ -0,0 +1,26 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+.text-input-container {
+    display: none;
+}
+
+.text-input-container.open {
+    display: block;
+}

guacamole/src/main/webapp/app/client/templates/client.html

@@ -17,12 +17,12 @@
             <div class="client-bottom">
 
                 <!-- Text input -->
-                <div class="text-input-container" ng-show="showTextInput">
+                <div class="text-input-container" ng-class="{ open : showTextInput }">
                     <guac-text-input needs-focus="showTextInput"></guac-text-input>
                 </div>
 
                 <!-- On-screen keyboard -->
-                <div class="keyboard-container" ng-show="showOSK">
+                <div class="keyboard-container" ng-class="{ open : showOSK }">
                     <guac-osk layout="'CLIENT.URL_OSK_LAYOUT' | translate"></guac-osk>
                 </div>