Using Classic Applications
When you open an icon for a Classic application or a document created with a Classic application, Mac OS X automatically starts the Classic environment and opens the application within it (Figure 38). The Mac OS X Aqua appearance disappears, replaced with the more sedate appearance of Mac OS 9.x.
Figure 38. This example shows a SimpleText document open in the Classic environment on a Mac OS X system.
While the Classic environment is in use, certain operations work differently than they do in Mac OS X: