Complex sentence: As opposed to Windows, all windows belonging to an application share the same menu, they can be hidden and manipulated as a group, and switching occurs between applications (i e groups of windows) instead of between individual windows.
Split into simpler sentences: As opposed to Windows, all windows belonging to an application share the same menu. These windows can be hidden and manipulated as a group, and switching occurs between applications (i.e., groups of windows) instead of between individual windows.