We have in the past decided to simplify the logon window by removing the language selection option. This was done to reserve some space for e.g. a third input field for two-factor authentication (see the blog post about Yubikey Zarafa authentication integration). The language can be set in the Settings application by the user after logging in. The server administrator can configure the language of the logon screen, but if the user wants to use another language, he's stuck with this until he has navigated to the settings.
Since the last beta release, new users are welcomed into WebApp with a welcome screen. Instead of going straight to the WebApp interface, users who log on for the first time can now change the language and a few other - frequently changed - preferences like the startup folder. After checking/changing these, he continues to the main WebApp interface. When the user continues to the WebApp, all the preferences are already set and he can quickly start working. There is no need to navigate to the settings to change them.
The list of preferences that can be changed in the welcome screen are based on what a user needs to have set to start working immediately. This includes the interface language, so that the interface will be loaded in the correct language directly the first time the WebApp is loaded. The startup folder can be set too, so that a user can decide whether he wants to load the Zarafa view with widgets or perhaps directly his mail, whenever he logs in.
He will also be able to define some of the calendar settings that will define how his calendar will be shown. Besides settings the first day of the week, he can also define his working hours that will be highlighted.
Under the hood
If you compare the welcome screen with the settings panel inside the WebApp, you will see some similarities in the way the settings are presented. This is because the welcome screen uses the same Settings Widgets as in the settings panel. This makes it easy to add extra settings to this welcome screen too. To do this simply utilize the insertion point "context.settings.category.welcome" to add your Settings Widget.
The Welcome Screen is shown prior to loading the WebApp interface. After you click on the continue button it will reload the page and now initialize the WebApp interface. The decision whether it will show the welcome screen or the WebApp interface is based on a setting.
When you have walked through the Welcome Screen Webapp will set this to false and the next time it will skip this step. If you want to develop your own Settings Widget for the Welcome Screen you can go into your advanced settings and either remove this setting or set it to true to trigger the Welcome Screen again for your next login.