Simple Question

I just started using Flash MX, and I have come across my first problem. I went on the Insert menu and created a new symbol, and i set it to Button.

Now above the timeline i have the Up, Over, Down, & Hit … eventually by default the focus is on the Up, which appears in red, however when i am left clicking with the mouse to move to any of the other (over, down or hit), the focus is still remaining on the Up.

What is the exact procedure in order that i can set the focus to any of the other states ?

Thank You