Running Boinc 5.10.29 on Mac OS X 10.5.1 ...
This bug occurs using both Rosetta and Seti@home...
I click show graphics to view current progress on work unit. After viewing said graphics, I click on the (x) to close the window. The window vanishes from view, but icon for graphics window remains on the dock. I am also able to view these icons using cmd + tab. Selecting the icon does not redisplay the graphics window, rather nothing happens at all. The only way to close these is to quit Boinc and restart the app. This was also a problem on 5.10.28. I know that I did not have this problem when I was running 5.10.28 on OS X 10.4.10. This error is continuously reproducible.
I looked for a similar bug before reporting this.