Problem with captivate mac, I can't modify my work

Hello,

I'm running captivate with macOs Big Sur 11.1

I can open Captivate but the slides are not centered on my deskspace. I can center it but when I try to modify somethig, (like insert a text) the slide image disapears and I can't do anything. 

How can I solve this problem?

Thanks you very much,

(I attack a video to show you the problem)