Preserving an issue for appeal in the middle of trial can be tricky.
The lawyer who represents a person in the trial court normally has to preserve an issue for it to be heard by the court of appeals. If the lawyer doesn’t object when something improper happens, the appellate court is not going to be as eager to do something about it.
Yet the trial court lawyer is worrying about so many things that preservation of an appellate issue isn’t always the right thing to worry about. It’s much better, for example, to have a strong shot at a not guilty verdict than to have an issue that you may be able to win on appeal. And, in trial, there are so many balls to watch, that it may be rational for a lawyer to take his eye off of one of them for a moment. Which can make for a harder appeal.