Our client has contacted MODx support with this issue (Jay Gilmore and Ryan Thrash have replied to him on
https://modx.zendesk.com/tickets/6564 if anyone reading this has access to it).
The questions he asked weren't quite enough to get to the bottom of it but after looking into it myself I still need some guidance. I am not sure if it is a core issue or a component issue.
The problem is that when a manger user uses the MIGx component it creates a model window for editing. If the user then grabs the top of this and throws it beyond the top of the browser the top edge goes off screen so it can't be pulled back down again. I have tried flushing cache, permissions, sessions the browser, but nothing happens. When I log back in, even using a different browser the modal window is still off the top of the screen. This information must be stored against the user's account, but I can't see if it's in a file that isn't clearing or in the database (I have looked at every table that looks like it might store this information, but nothing). Any ideas where this kind of information is stored and how to reset it?
Any help would be appreciated.