For the cable slides, which is a give-and-take system, the cables are what keeps the room plumb/level... and not a track or rollers. There are rollers, however they do not provide balance, only a single rolling surface. Think of a logger balancing on one log.
If one set of cables (top or bottom of either the inside or outside) are too loose, the room will tip over until the slack is taken up. Since the room runs up against the wall, it should get plumb once fully open or closed. That only works is the slack is on top though, due to gravity.
A quick way to check is to full open the room then check slack on the outside cables (all four). Simply taking up the slack will get you pretty close.
Although a little more difficult, fully close the room then check for slack on the inside cables.
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