I made a bar graph with Prism 4. When I changed the shape of the graph, all the bars vanished.

This is a bug that we will fix in release 4.03 and 4.0c.  To work around the problem:

1. Click Change and then choose Bar Appearance.
2. Go to the second tab, and change the graphs from vertical to horizontal (or the other way around).
3. Click OK. Now the bars are back, but run the wrong way.
4. Double click on a bar to go back to the Format Bars dialog.
5. Go to the second tab, and choose the other direction.