Does a represented criminal defendant have a right to be present at sidebar conferences with the judge?
Sometimes, yes.
It's harmless error here. And when the sidebar concerns only issues of law, the defendant can be left sitting in his chair (at least as long as the attorney's allowed to consult with him if counsel thinks it's necessary).
But during, for example, voir dire, when a juror's privately telling everyone why he might not be able to be fair, the defendant has a right to hear what's said.
So you gotta let him approach the bench alongside counsel.