Animator controller kept moving and now it disappears

It just kept moving, to an extent where everything just disappears.
Now I don't even know where are those animations, and I can't edit them because it's gone.
What should I do? It moves a lot, and I think I have spent too much time (probably 100+ times) moving them back to the middle of the screen.

I can't scroll vertically in the animation controller, so everything just got stuck in somewhere-out-of-reach.

Someone please help me. I tried finding solutions to this bug, and my effort is being washed down the drain. It's my third time posting this thread, and this unreasonable bug is demoralizing. I don't want to quit using Unity due to this corrupted and unsolvable bug.

 

you mean cannot pan the view with middle mouse button down?
or press ctrl+a to select all, then F to frame in