Need Help Controlling Tag Browser in Power Chart Component

You don't. If you need a "custom" tag browser, currently you're only choice is to develop it your self. Not trivial.

There are many posts on the forum detailing the limitations of the Power Chart component up to and including its current itteration.

One of the most popular ones:

Long story short if you chose to use the Power Chart component you're stuck with it's limitations. I'm confident that someone at IA is working on these, however, I wouldn't expect to see any changes until after 8.3 sometime.