Certain sash windows just not coming up right the ones with dodgy paint work or dodgy woodwork seem the culprits ,
i normally say althou 1st cleans are normally flawless a window or 2 where the paint work or wood started chipping may show a little bead which should flush out, but this particular window is always leaving such a noticeable bead.
whats the best way to describe this? because i want to say i can not be held responsible for this problem ,pure water can not streak , therefore you have a problem with your frame work .
i wana word i correctly forgot what its called when the water mixes with the paint work too.