mine do the same, thinking of a "velcro" tab stuck to windscreen corner to clip to, to stop top front corners walking outwards, or elastic type strap from sidescreen top front to three sided guide on soft top front screen rail.
The other train of thought is to stiffen up door sockets with a wood or similar block inside door frame, so as to reduce flexing, I actually lost a side screen peg due to this while coming back from Ballarat last year.