Specifically... a bit of plasticy fabric material (to protect the toe wear area) has started to peel away from the main body of a pair of GTX trail shoes. What can i use to stick it back down that won't ruin the shoes? Will Gorilla Glue damage the fabric?
Shoe goo or possibly aquaseal adhesive/sealer I'd say.

Stormsure would also work nicely. You can buy multipacks of 3g (or similar size) tubes for the same price as full sized tubes too. Works really well as single use tubes and doesn't spoil 'til the next time you need it.
Cheers kids. Just ordered a multipack of stormsure.
I used Stormsure to repair a cut in some Goretex walking boots.
Because of the location of the cut I didn't have much hope it would work. It was right on a flex point.
But it's done a really good job and is still going strong 12 months later.