It happens in the latest CC builds 6621, 6623, 6627. U go to Settings -> Compiler and Debugger -> Global Compiler Settings -> Custom Variables -> Add, and u put "$(asd)" for Key and "asdfg" for Value. Hit Ok, and Ok. U will get a Runtime error: The application has requested the Runtime to terminate it in an unusual way. I know, u shouldnt put &(asd) for Key, but it should show a warning and not make the program hang.
Hope my bug reports help developing CB.