1) Load up the usa_counties.shp file
2) Select "Delete Feature" tool
3) Select a Geometry to Delete
4) Hit the "Redraw Map" button.
First, the features do not always get removed from the map when clicked on with the "Delete Feature" tool but instead require a redraw for the changes to show up.
Second, the selected features aren't deleted but instead apparently random other features are deleted instead.
The pictures try to show the issue. The first picture shows the feature I tried to delete. The second picture shows that happens after I delete them and redraw the map. As you can see the features I selected to delete are still there, but other random features are deleted instead.
Note: This is probably related to the Edit Tool bug submitted earilier (http://jira.codehaus.org/browse/UDIG-1508)