With the window menu items, you can manipulate the appearance of the open windows.
In Amateur Invest it is possible to have opened one instance of the more important windows.
If a window doesn't have the "minimize" icon enabled, you have to close that window, before other windows become available.
When a window contain a "minimize" icon in the top right hand corner, it means that it is a window, that can stay opened on the screen, while other windows are also open. This makes it possible for you to see several windows on screen at one time, and to switch between them easily.