An all female group were talking about things like terrorism, liberalism, tolerance, the poverty gap and international co-operation.
The teacher came over to their table and asked them if they were talking about futuristic fashion.
This happened. It shouldn't have. Girls should not be pigeon-holed in this way. That teacher probably doesn't have the first clue that he was being sexist. He probably didn't mean to cause offence. People who interact with kids do have a special responsibility to engage their brains before they open their mouths, though.
The great value of the Everyday Sexism project is that it shows how commonplace these sorts of incidents are and raise awareness of what sexist behaviour is. Many women experience examples of sexist, demeaning behaviour on a daily basis. They are fundraising now to expand their operations. You might want to consider giving them a donation here. I have. A word of warning, though. The video is quite triggery for sexual assault.