The glass cannot be secured entirely because it needs to slide so the windows can open. Since this is the case, one of the major concerns is preventing the glass from rattling in the channels from excessive play. We replaced all the felts and liners using Keen Products and, while we were at it, we took a few extra steps to ensure there wouldnt be any problems down the road. Dewey uses spray adhesive to hold the felt for the channels. Make sure the felt is down completely in the channel and that it isnt bunched up anyplace. If you dont do this, it will cause annoyance later when the window doesnt operate smoothly. Also, on the end of the channel, Dewey likes to fold over the end of the felt on the end so it wont mar anything as the window moves up and down in the channel.