How do you use visual studio tools for office with xml ribbon UI to get a user control to come up when a button is click?

I am using XML ribbons for my UI in VSTO. I开发者_如何转开发n Micrsoft word, sometimes when you click a button in the ribbons, a user control pops up. How you you get it to pop up?

I figured it out. I just used a Custom task pane.