While I was painting the body cladding and side mirrors this weekend, I decided to fix my window problem and it was easier than expected.
First, I put grease in the rail which helped speed up the up and down motion of the window. But I noticed it still derails.
There's an access hole on the top corner of the door directly below the door popper. I used an over sized flat head screw driver and used it as a lever to push on the rail towards the window. This cured the derailing but the window still binds as it is going down.
I pulled out the lower part of the door where the window mechanism is mounted as needed. The metal is kind of flimsy that's probably why over time, the window mechanism gets out of spec. and causes problems.
Hope this helps somebody...