Those white guides were part of the new regulator. They may not have been in proper position when it was installed. Once the regulator is in place and the glass attached, those guides should stay in place (at least until the keeper part breaks off).
I don't know if other Isuzu's had similar problems. IIRC most other Isuzu windows are flat while ours are curved. That may make the problem unique to the VehiCross.
If I can get out of work early enough to hit the parts store, maybe I can come up with a quick solution for you. The regulator I'll be 'operating' on is an extra so if I can fix it, you can beta test it for us.