Scene screen disappears when resizing puppet

Hello
I'm trying to use the new movement library as well as body tracking. But when I import my own puppet into a scene it's allways to big for the scene and when I try to reduce scale and move position to fit the puppet into the scene, the scene screen moves away from the center and becomes invisible (I have to reduce the zoom level to less than 5% to see it on the main screen as shown in my screen capture... It's doing that even with your puppets - simonthefox for instance in the screen capture, as soon as I put a puppet of mine in the scene, even after deleting it). Is there a special feature I don't know of, to recenter center screen ? Or is it a bug ?

Thanks for your advice
Ivan

Screen capture : 
https://ibb.co/PYfzwmq