I spent an hour experiencing a blacked out character inventory window last night, and found the culprit eventually: ShowMotifs.
The inventory window would also 'lock', only by opening friend list or mail from the chat window, could I get out of the inventory window.
So if you're experiencing the same issue, disable ShowMotifs until it's fixed.
edit: According to ESOUI, the developer has uploaded at fixed version today
Edited by Travestynox on February 14, 2017 11:08AM