Fob sliding out of pocket

Not sure what has changed, but when the Prius key fob is in the (front) pocket of one of my pairs of pants, and I sit in a particular chair which tilts back slightly, the fob sometimes slides out of the pocket onto the chair. So far it has done it three times, and all three times I only realized it after going out to the car and not finding the fob in my pocket. The odd thing is that both the pants and the chair are old, the other objects in that pocket are my change purse and key case (both leather and the same as they have always been and the fob is placed beneath them), and the fob never used to do this.

So now I'm trying to think of some way to more firmly secure the fob that won't make using it too much of a PITA.

1. I have seen the threads where people attached the fob to a key ring via the little metal loop - and found themselves with the metal key, but without the fob, after something or other pushed the release button. (It may have been a different generation Prius.)
2. I could make a style change and only wear cargo pants with pockets that fasten shut.
3. There are key fob holders but since this car doesn't have SKS, that would mean moving the fob in and out of the case a lot. Anybody ever tried one?

This makes me pine for the days when cars just had keys, because those could go in with the other keys and didn't present any special problems. Well, other than sometimes all those keys dangling on my leg while driving a car.