STEPS TO REPRODUCE
1. File > New.
2. Pick the Rectangle Tool.
3. Click the center point and right and up.
4. Type "2,2" and hit enter.
5. Pick the Line Tool.
6. Score the square along the centre line from the left side midpoint to the right side midpoint.
7. Switch to ISO view.
8. Pick the Move Tool.
9. Click the center line and move in the blue direction.
10. Type "1" then hit enter.
11. Pick the Rectangle Tool.
12. Draw a square roughly in the middle of the face facing you.
13. Pick the Push/Pull tool.
14. Pull the newly created square out of the face.
15. Zoom to Extents.
16. Switch to the Right view.
17. Heal the square on the inside (pick the line tool, and draw along one of the inner sides on the inside of the object.
17. Pick the Rotate Tool.
18. Rotate slightly in any direction, watching the most recently created face.

ACTUAL RESULTS
There is flickering -- you can see the colours of the faces on the other side of the "roof" surface where the lines intersect the roof.

EXPECTED RESULTS
No flickering.

TESTCASE
Load the attached file and pick View > Tourguide > Play Slideshow.