The Gantt chart allows you to compare the baseline and scheduled actual duration of tasks and milestones. If you have baselined your project, you can enable baselines on the chart by selecting it from the Features menu options.

When you enable baselines, the Gantt chart displays grey bars below each taskbar representing the baseline. You can use the baseline to compare the original start and end dates with the actual dates. 

By hovering over the baseline, you will be able to see the baseline dates and duration. If there is a schedule slippage the tool-tip bubble will display the exact delay duration.

You can also see it on the Edit Task form.