Executable for Debugging Session Dialog Box
This dialog box appears when you try to debug a DLL for which no executable is specified. Visual Studio cannot launch a DLL directly. Instead, it will launch the specified executable. You can debug the DLL when it is called by the executable.
Once entered, these settings are stored in the project Property Pages, so you will not need to enter them again for subsequent debugging sessions. If you need to change the settings, you can open the Property Pages and change the values. For more information on specifying a executable for the debugging session, see Debugging DLLs.