troubles with formatting bar styles

I'm new here, trying to teach myself how to use MS project.

Using the Step by Step MS project 2013 book and exercises.

It's all going smoothly, and im getting the hang of it. Except for the basic issue of not being able to format the bar styles.

I followed the instructions step by step but notging seems to happen.and the 

I clicked in the task name of the task I want to format. then I got to the Format tab, then I select a different style in the bar styles selection. The book says it should change colour. But in my case nothing happens. I thought nothing of it and moved on. Now I need to do the same for the predecessors. 

It's the same basic steps, but the damn colour won't change.....

Any advice, tips or help would be really helpfull.

Thanks