The user has the option to sort by column, simply by clicking on one of the identifiers on the top bar. In previous figures such as Figure 2.5.1-6, the user has clicked the 'Building' identifier, and the Classrooms window is sorted in ascending order by building number. 

Figure 2.5.3-1 shows a Classrooms window which is sorted by size.

Figure 2.5.3-1: A Classrooms window filtered by room numbers beginning with "21" and ordered by room number.

The user also has the option to filter through the Classrooms window, as shown in Figure 2.5.3-1. The user has chosen to 'Filter by' 'Room'. As the user types in parts of the string, the list is filtered real time, and only the classrooms which fit the search are shown. The user types in the number "21", the list updates, and only the classrooms with a room number beginning with the number "21" display.