dlaude6;

The window felts or runners that the glass slides in. One on each side, and also put some grease, lube down where the arms attach to the bottom of the glass.

You will want to use a silicone type spray in the tracks. Worse case use wd-40. You don't want a build up in there with dust on a greasy spray or you make the issue come back faster.
You can cheat and just roll window down all the way and spray down the sides with the straw an up the top. Run window up and down a few times to lube. Try this way first before going thru the motion of opening panel.