GUACAMOLE-724: Automatically focus the first client if no client has yet been focused.

guacamole/src/main/frontend/src/app/client/services/guacClientManager.js

@@ -232,7 +232,8 @@ angular.module('client').factory('guacClientManager', ['$injector',
             clients.push(service.getManagedClient(id));
         });
 
-        if (clients.length === 1) {
+        // Focus the first client if there are no clients focused
+        if (clients.length >= 1 && _.findIndex(clients, client => client.clientProperties.focused) === -1) {
             clients[0].clientProperties.focused = true;
         }