In the taskbar of Windows 10 and most versions of macOS, all of an application's windows are grouped under a single icon. This makes the user interface less cluttered, but it does mean that an application that opens many windows may be a little harder to navigate as there isn't a simple icon click to show a specific window. Add to this the behavior of macOS and Ubuntu Linux (or other distributions using the Gnome desktop) to group windows under a single icon in the task switcher (keyboard Alt + Tab) as well. With Gnome, you can explore the windows under an icon by pressing the down arrow key or using the mouse, but on macOS, you need to use an alternative keyboard combination (Alt +~) to cycle the windows of an application.

This trend to group windows may impact the design of applications that present multiple windows; if every time you launch the application, it opens three windows, then; after opening three documents, you could have nine windows open. The most common approach in this situation is to have supporting windows open just once, making their tools or information assume the context of the current document (probably the topmost window). However, this may add complexity to your application as it would need to communicate with other instances of the software that are already open.