[mrguyorama]

>but isn't is how every frame-less car door works?

It isn't. My 2004 toyota solara had frameless windows and didn't play any shenanigans with it, and as others in this rough thread have pointed out, subaru doesn't either. I don't know where you got this idea but you've managed to ingore two very popular brands at minimum so maybe you should reconsider some things

[bgee]

I see, not every frame-less door has this mechanism.

In the case of Toyota Solara, how does the glass fit with the seal on the A-pillar and roof? The roll-down mechanism is required because the glass on those doors have to be "inserted" into the seal.