One last question, I hope
The balance sits in a slot on the sides of the window. Some of those slots are blocked at the upper end with a white plastic piece affixed to it. Some of the windows I am repairing are either missing that piece or it is broken - causing the balance to slide up without the window...so it doesn't function. What is that plastic "stopper" called? Once I replace it, how do I affix it to the metal window? Is there a special adhesive?
Thank you