I have Kobly double hung windows. On one, the front one slides down like a rock and wont's stay in any up position. On a few others, when you opne the bottom on, the top on slides down part way. Is there anyway to adjust the tension (or something) to not make them slide so freely? ( they are about 6 years old and are the ones that pop out for cleaning.) They are clad and the insides are some kind of plastic) Also, does Kolby&Kolby still exist?