removing thumbnail page boxes at bottom & black for background

[blackxacto]

1. I cannot see how to remove the file windows at the bottom of the main thumbnail window. How?

2. How do I color the gray on the right side to black? It looks like some background, but background to what? Where do I change the gray to black?

[Franky]

Hi,

If you close your Category Sets panel in bottom left, the bottom area is delete ?