gvSIG-Desktop 1.12. User manual
gvSIG has a tool which allows you to insert a box in the map.
If you wish to insert a box, select the following button from the tool bar:
Left click on the map area you wish to insert the object in and drag it to create a frame which will define the future box size.
When you drop it, a window will automatically appear for you to define some of the box properties.