One more approach that can help your application to be easier to navigate is to split the content into multiple windows. Each will be a different view of your application, within which the appropriate toolbars or menus can be presented for the current context. As shown in our GoMail examples, we compose new messages in a separate window; this allows us to group editing-related items close to the input fields and allows us to simultaneously be drafting multiple messages without cluttering our email browse window.

Of course, multiple windows won't necessarily have the same semantics on different platforms. If we were to take the same approach on a smart phone device, it would be common for the compose window to be presented as an overlay to the existing application. Whether the user can switch between that mode and the browse window may be down to the operating system's design or we may decide that, when running on a smaller device, the compose window should be a modal window (that is, it blocks access to the parent window. This is discussed further later). 

Yet another approach that we saw in Chapter 2, Graphical User Interface Challenges, was to have multiple windows for the main focus of the applications. These peripheral windows are typically for toolbars or detailed information/control of the content in the main window and can be particularly helpful in content creation-based applications. With the content expanding to fill the whole of the main window, the toolbars and context actions have been placed in separate windows to keep the user focused. This type of layout and navigation is usually adopted in pro applications where the user knows the domain well. The added complexity of this approach can lead to confusion for early users of a product and so we, as application designers and developers, should be mindful of the number of windows or different layouts and contexts we present in our user interface.