Stacked Bar Chart for Progress to Goal

I need to create a widget to show progress towards goal for a few of our current campaigns. So far, I've created a widget to show membership progress to goal.

Because I need to include a couple other campaigns in this widget, I thought it would be better to use a stacked bar instead of two bars, so the green bar looks like it "fills up" the blue bar as we move toward our goal. I can't figure out what I would break by to make this work. I've tried various things, but everything I've tried just "turns off" one or the other of the bars and doesn't stack them.

Anyone have a suggestion for a criteria I could try?