A mouse or any similar point placement tool is absolutely necessary to fully utilize XQuad. The norm on X terminals and Unix workstations is a mouse with three buttons. However, some Unix systems or X servers running on PC compatibles more frequently use a mouse with two buttons. Macintosh, for the most part, uses a mouse with only one button.

XQuad uses the three buttons to manipulate different functions; however, the middle and right buttons are only used to shortcut other manipulations. These buttons are therefore not indispensable; full utilization of the application can be achieved with a single mouse button.

Using the three buttons in XQuad:

1. The left button is used to execute all point placement operations, selection from lists, selection of a button or an icon, and drag and drop functions. It is possible to fully utilize XQuad using only this button. The only two keys which might be used in conjunction with the left mouse button are:
    
   • The Shift key in cell selecting, selection copying, and line or column inserting.
      
   • The Ctrl key in certain dialog boxes listing elements. Using this key simultaneously with the left mouse button allows the user to select several elements from a list.
     This key is also used in sequence extending.

   
   A double click with the left mouse button is used in the following situations:

   • double-clicking on a frame opens the 'Frame Attributes' dialog box.
      
   • double-clicking on a filename in a file selector.
      
   • double-clicking in a text field selects an entire word. Triple clicking selects the entire line of text.

   
   

2. The right button is used in the following case:
    
   • to abort an operation in progress. In some action modes, you often have to set a source location and a target location thanks to the left mouse button. Once the source location set, you can click on the right mouse button to abort the operation.

1. The center mouse button is rarely used. However, it may be useful in the following situations:
    
   • moving a cell selection.
      
   • to perform a paste command in a text field in order to insert a piece of copied text from an xterm or any other X11 application using memory stamps. In the text editor the user chooses the memory stamp to be pasted by simultaneously pressing the shift key and the center mouse button.

To know what operation mode XQuad is in the user must observe the shape of the mouse cursor. Each operation mode corresponds to a specific type of mouse cursor.