When a network window is re-scaled, the size of Nodes and Labels remain fixed; this is because the nodes are symbols that represent the centre of the object, or the junction of links. 

When the scale of a picture changes so that the text becomes unreadable,  it is displayed as a black box showing the location of the text but not the actual characters. The size of the viewed window can be changed in four ways:

Scale Menu Command

The scale factor is a mapping or engineering form of scale with real-world units in metres (or feet). The default scale at which the network of a new database is initially created is 1:1000. This type of absolute zooming is done about the centre of the display window.

Scaling Icons

Zooming can be performed relative to the current scale factor using the "scaling tools" from the toolstrip. The tools are tied to fixed scaling of 2X for zoom in and 0.5X for zoom out.

Window Scaling

The size and location of a new window can be defined by zooming-in to a rectangle proportioned to the shape of the display window. A rectangle similar to a selection rectangle is created by first selecting the Window Area In Tool from the toolstrip and using the mouse button and dragging a rectangle around the area of interest. When the mouse button is released, the window maps exactly to the proportioned rectangle. Both the size and position of the zoom box can be manipulated in this way.

A zoom-out action may be performed in a similar manner by selecting the Window Area Out tool from the toolstrip and following the above instructions. The dotted rectangle shown on the screen will indicate by how much the current full window will be reduced and where the current window will be shown.

Fit Window

A "world rectangle" is defined as the minimum size rectangle enclosing all objects including background pictures and text objects. The view window can be made to automatically fit the display by giving the Fit Window menu command from the View Menu. This function is also embedded in the toolstrip by selecting the Fit to Window tool button. 

When the window is zoomed in or out, the size of Nodes and Text may remain fixed relative to the screen or may be scaled proportionally depending on whether the "Real-World size" or "Display size" option is chosen as the display attribute. By default the nodes are symbols of fixed screen size representing the centre point of an object or the junction of links.