I just watched Jenny's new tute on zippered pouches and loved it! I have all my materials to make my DD and DIL each one of the Tumbler bags. My DD asked if it had a zipper closure or just the tab. I asked her if she wanted a zipper and she indicated she would. So now, can a zipper closure be used on this bag? Would it be done like the zipper pouch? I need to go back and watch the Tumbler tute again but wondered if this could be done and has anyone used a zipper on that bag or another? TIA!!