Each bar represents one task or milestone. The bars are grouped by resource name.
You can use Preferences from the Edit menu to specify which bars you want showing and whether you want slack time displayed.
-- part contents for background part 7
----- text -----
The planned bar (the wide one) represents the total elapsed time allocated for the resource to work on that task.
The actual bar (the narrow one) represents the actual elapsed time for the task as a whole, not just the resource’s part of it. If the resource’s time is less than the task’s actual time, the resource’s time is also indicated in the actual bar, by a dotted line.