Just got off a TG 787
Took of at 1150, 15 mins later, windows dimmed and remained so until 10 mins before landing.
Most annoying.
You need to submit a complaint to the airline.
I would ask them to either take action or give you some sort of compensation.
My dear friend works on the 787 (a different airline) and she tells me in her manual it states that the windows must be left alone so pax can control them (except for takeoff and landing of course).
Are cabin crew really this controlling on the 787 over the windows?
Working up the pointy end, I really do admire and respect the cabin crew I fly with for what they have to put up with and of course the huge amount of training they have to do. In my opinion they aren't paid enough (but then again, what profession is?)