The Progress Dialog provides feedback on the progress of long operations. It appears for operations that take more than three seconds to complete. The Progress Dialog displays several bars that show what percentage of an operation is complete.
You can also enable an animated system tray icon while the Progress dialog is up (see the setting on the General page of Preferences - Application Settings. This helps let you know the status of a complex operation if, for example, you switch applications while waiting.
The most important bar is the top one, called the "Main Completion Bar". This bar shows the amount of time left for the overall operation to complete. The operation being carried out is named in the Main Title caption area.
Below the main bar are subordinate completion bars. These bars show the amount of progress for sub-tasks. The second bar from the top shows the remaining time for the current sub-task of the main task. The third bar shows the remaining time for the current sub-task of the current sub-task of the main task.