I've been digging through the internet looking for an answer on this. As best I can tell, if "allow modification via structure" is enabled on my extensions, my users should be able to drag and drop issues on the structure. I as the board owner am able to drag and drop but none of my users have the options. I've tried playing with the permissions and reviewed all the settings.
It's not just drag and drop. The arrow buttons that allow you to move issues around are also greyed out for my users.