Try using one or 2 zip ties. It will give you enough force to keep it tight and although it doesn't fix the original problem, it will work.

This is my first post. The reason I sign up to this community is nothing but to answer your question (and other with the same problem).
Whatever you do, taped, bag, glue etc. what would I say is: STOP FINDING A WAY TO MAKE THIS FAILURE BE TOLERATED.
How can be a big company like Line 6 make a major mistake on design product

Right now, I really need wireless guitar set and I've got enough money in my wallet and ready to spend on local music store to grab the G30.  But after reading many customer complain in the net, I'm gonna look another brand.