If you want to change the appearance of all events of a certain type, you probably don’t want to go through and format each bar. Instead, you can double-click in a blank spot of the Gantt chart (or click the Format menu and click Bar Styles) to open this dialog:

There are a lot of complex things that you can do with this dialog, but it’s essentially the same as the Format Bar dialog that we just looked at. At the top, pick a task type. Then, use the fields at the bottom to change that task’s Gantt chart appearance.

Note that there is no Reset button in here, and that these changes cannot be undone, so you may want to back up your project before opening this dialog.