Window groups can be created by opening an empty window by double-clicking on the border of an existing window. Dragging and dropping selected items in this empty window will open as many windows as the cardinality of the selection all grouped inside the empty window. Figure 4 shows the result of creating a window group for visualizing all new incoming mails from a person. Users can add more windows into a group later as well. A window can be removed from a group by simply closing that window.
Hierarchies of windows can be created similarly by opening an empty window inside another empty window. This is done by selecting the operation from the menu on the left gadget.
Figure 4: Creation of a window grouping visualizing new incoming mails from a person.