Okay. Yes. Judge Graber is correct. I'd have ruled the same way. There's no reversible error.
But doesn't it nonetheless seem unseemly to do what the district court does here? First, it refuses to exclude the prosecution's main witness (indeed, pretty much the only one) from the courtroom during the testimony of the other witnesses, notwithanding Federal Rule of Evidence 615, which generally requires such an exclusion. So the prosecution's principal witness gets to hear everyone else testify, and potentially alter his own testimony in response.
Plus, the district court doesn't make this witness go first, which would somewhat solve the resulting problem. Moreover, the district court lets this witness -- a law enforcement officer -- sit at counsel's table throughout the entire trial. A pretty prominent place. A place that few victims (here, the charge was assault on this officer) get to sit.
To top it all off, the court finally refuses to give a standard instruction -- requested by the defendant -- that says that the testimony of law enforcement officers shouldn't be treated more favorably than the testimony of others.
Okay, you can address each point one-by-one and say, yes, no error, no reason to reverse.
But what about dropping a line that says that this isn't exactly an awesomely neutral way to run a criminal trial?