I'm stuck in 3d View

Hi I'm totally new to after effect and I'm trying to follow tutorials along, but i encountered one issue. when i create 3d objects (sorry if i don't know the technical names yet) and i activate the 2 view camera to edit the depth, sometimes the bars doesn't move at all, and then if i try to get out of that view (going back to 1 view), to try a different approach, instead of going to the main composition, AE only shows the black screen that's supposed to control the main comp. I cant seem to find a solution for this other that reopening the program completely, even if i rest the workspace, no matter what i do it just wont go away. Any solution to this?

PS: Also sorry about any grammatical mistakes, English is my second language.