Sorted this UI bug by reinstalling the game. Hope it doesn’t happen again. The dev team should look onto to at some point though. Alt & L should make any opened windows visible in the screen.
I cannot progress the Traces of Battle 3 quest it is stuck with the following error output:
‘There is an ongoing quest dialogue. Close the quest dialogue and try again.’
I tried many things resetting the UI using the settings and ALT & L nothing.