JitMagic is a simple tool that allows you to have multiple Just-In-Time debuggers at once.
You have to set the following registry keys:
HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\Windows NT\CurrentVersion\AeDebug\Debugger
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\AeDebug\Debugger
To use JitMagic.exe:
C:\Projects\JitMagic\JitMagic\JitMagic\bin\Debug\JitMagic.exe" -p %ld -e %ld
See Configuring Automatic Debugging for more details.
To use this with Visual Studio's JIT debugger you need a special hook to make the Visual Studio version selection dialog work properly. For some reason vsjitdebugger.exe will check the contents of the Debugger\AeDebug key and if it doesn't point to itself it will not display running Visual Studio instances.
You can use AppInitHook (module WefaultMagic injected to werfault.exe and taskmsg.exe) to get this to work.