Is there a way to change the colour of this gray area? I would like it to be white. I like to use this area as a mood board, so it helps if I am working with the same background colour.
Another alternative where you can switch in and out of it being white or grey (e.g. if you want to focus on your work, then focus on the mood board items around it):
Turn on Overprint Preview (
View > Overprint Preview).
This turns the background white - then, it reverts to the default when you turn it off. Slightly more convenient for toggling than preferences.
Overprint Preview is also used if you have overprinting settings and you want to preview them, but if you're using overprinting, you probably already know about that... If you've not set anything to overprint, it makes for a handy way to easy switch in and out of having a white background.