I used Boa on many different PCs with different operating systems and sw version and I didn't have this problem before, so I think it depends from my actual environment.
I run a FedoraCore 6 x86_94 with Boa version = '0.5.2' and:
everything compiled for 64 bit environment.
Every time I click on X to exit Boa application I get the crash of the running X-server.
I tried it with and without opened files.
I tried it whith freshely created preferences in my home directory.
Each time appens just the same.
I don't know how to get more information about this crash. I tried launching boa from command line and redirecting output on a file but I didn't get anything.
On this new PC I get much more frequently the 'copy, cut and paste' problem about what I told you in the past.
Perhaps it could depend in some way from hw performance???
Let me know if I have any way to indagate further this problem.