Clearance.....
Lay the window into the frame and check the clearance. Make sure the window frame is even with - or slightly below - the face of the top and bottom sliders.
Image URL for use on other sites:
http://images58.fotki.com/v448/photos/1/15405/6542395/P8030005-vi.jpg
Link to send via email/instant messenger:
http://public.fotki.com/khamilton/models/model_how-to/how-to-make-simple-/p8030005.html
Code for a Fotki Journal:
[photo id=wdbwqqsbsbfrrtwxkgtkrtdtdd type=vi style=1 align=no link=photo]