In 9.0:

1x EventScreenshot\EventScreenshot-0.2.1.lua:22: attempt to call method 'SetBackdrop' (a nil value) [string "@EventScreenshot\EventScreenshot-0.2.1.lua"]:22: in function <EventScreenshot\EventScreenshot.lua:10> [string "=[C]"]: ? [string "@Bartender4\libs\AceAddon-3.0\AceAddon-3.0-13.lua"]:70: in function <Bartender4\libs\AceAddon-3.0\AceAddon-3.0.lua:65> [string "@Bartender4\libs\AceAddon-3.0\AceAddon-3.0-13.lua"]:498: in function InitializeAddon'
[string "@bartender4\libs\AceAddon-3.0\AceAddon-3.0-13.lua"]:623: in function <Bartender4\libs\AceAddon-3.0\AceAddon-3.0.lua:615>`

Cheers

Fixed in 3bb651b

0.2.2 available on Curse whenever it gets approved