Why all my windows, viewports and everything became white?

I was using Unreal engine with no problems, until i close and reopen the program, and everything is white, and cannot select anything, can’t use some options in the blueprints, can’t use matinee, and i cannot see anything, i don’t know if i activated something but only by starting another project everything work again.
there are some pictures of what its looks like.
Hope someone has an answer