[Newbies] Newbie question

[crowd_struts_07 at icloud.com]

Is there a way to stop the endless debugger windows when a process goes astray?  I had code in a workspace which I tried to stop with CMD-. (Mac) which seemed to work most of the time but the last time it just created an unlimited number of debugger windows.  I close them just to see more reappear.  Besides writing better code :-) is there a way to stop the program and the endless debugger windows?  Thank and apologies if this is something covered already. 

Regards
Pete