Mmmm, really what I want is to debug one instance of CB with another instance of CB. Maybe a different version would do. I need to run the debugged instance using some test project to edit.
This is something I (and many others) do almost every day, and it does not involve any special juju powder.
Compile Code::Blocks as usual and hit the "debug/continue" button. Set/Unset Breakpoints by clicking the margin.
If your debugger is set up correctly, it's really as simple as that.
The three most well-known causes (which you should check) for having problems with breakpoints are:
a) not compiling with debug information
b) compiling with debug information, but stripping the executable
c) setting breakpoints in class constructors
What concerns me is running two debuggers at the same time (and setting breakpoints in both). This is something I never tried and which I think might possibly not work.
Luckily, unless the debugger is the very thing you want to debug, it isn't necessary, either.