Locked patio door jammed open?

this is hard to answer but i have tried to envision what the door has done when you have yanked it.
the door runs on rollers at the bottom on a raised grooved metal strip. when pulling it is possible the roller furthest away from the handle has jumped off the groove whilst the one closest to the handle has stayed on. this would explain the door being allowed to open as the offset roller (ungrooved if you like) would lead the grooved roller. on closing the door the grooved roller would pull the offset roller against the groove if you see what i mean. if so simply lift back onto the groove.
however it is possible the rollers or other parts of the door have been damaged and without seeing it, it is really hard to answer correctly

levi lewy
August 2008