While on the topic of mules...I'm wearing these mules around the house this morning, evaluating comfort and walkability because I like how they're looking with my cropped pants from the last few years.

One thing is annoying me, and perhaps it's not so hard to solve, so I thought I'd ask here:

The insole at the toe seems a little loose -- it starts to wrinkle up under my toes as I walk around. I can see this becoming a serious annoyance in very short order if I start wearing them outside of the house, where I'll be walking far more. I've had this happen with other shoes before, but I would normally just put a little insole inside to correct the problem. With a mule, one of those insoles would be visible under the back of the foot.

Has anyone successfully conquered the problem of the wrinkling insole?