^ if the pistol is too far off of the panel, which it is on the blackhawk, it flops about endlessly, and the only way to keep it from flopping around is to tourniquet it around your thigh lol
Otherwise, a HIP holster is best, a dropleg platform but worn very high. This limits it's movement and the effect of flopping around.
On other droplegs, the obvious application is to have it light and very slim in profile to prevent that flopping about. I've also found that most droplegs seem to incorporate some sort of grip pad, or grippy rubberized strapping. This is totally ridiculous and doesn't work.
Most droplegs work their way down, then either pull your pants up or take your belt down with it. The fact is, unless it's sewn directly onto your pant leg, the darn thing is going to ride down no matter what you put on the back of it. So the best solution is to just LET IT ride up and down. Remove any sticky material from the back of the dropleg or the strap, let it slip, and simply secure it from moving around your leg by attaching the two belt straps as far apart as you can.
If your dropleg only has the one belt attachment, it sucks.