I see.
So I thought about this again, but now I don't see the point of the `ipkernel_qtapp` example anymore (except that it was there before `inprocess`, of course).  The only difference I can see is that one cannot (easily?) connect to the inprocess kernel, as `%connect_info` raises an exception (`MultipleInstanceError('Multiple incompatible subclass instances of IPKernelApp are being created.',)`), but this shouldn't be a serious issue for debugging purposes and perhaps it can be fixed in the inprocess kernel itself?
If I am not missing anything, I will just mention the third option in the docs instead.