Debugger proceed of attached process waits forever for process to terminate

[martinmcclure]

Clicking on "proceed" in a debugger waits for the process to either terminate or re-enter the debugger. This is appropriate for a process directly launched by an evaluator, but not for other processes.
For any other process under debug, the debugger should wait a few hundred milliseconds in case the process terminates or wants to re-enter the debugger. After that time has elapsed, the debugger should close, and if the process wants to be debugged after that a new debugger window will open.