The next section of the main dia window begins with a choice of sheets (i.e., shape libraries). Many are included by default and new ones can be added (see Section 23.7). Selecting one of the available sheets (by choosing from the pull-down menu that is labelled UML for the Universal Modelling Language in the above sample window) will display a collection of shapes associated with the particular sheet. (The sample window includes the shapes useful for drawing UML diagrams.) Some shapes, when selected and placed onto the canvas, have text associated with them and will grow in size depending on the text you type. An example is the Text box button.
Increasing the height of the main dia window will often allow you to see all of the available shapes of any of the sheets at one time.