Can't exit spacebar preview
If you press space to preview a file full screen, then click away to another application (on a second screen) you then can't exit full screen preview. The only solution is to close and reopen bridge. It doesn't crash - you can still pan and zoom the preview, you just can't escape its clutches!
The mentioned issue is fixed in the latest patch release #220.127.116.113, Please install and confirm if that fixes the issue.
You can refer the issues fixed in the patch @ https://helpx.adobe.com/bridge/kb/fixed-issues.html
Nancy Woods commented
They Fixed It Wooo Hooo!
Yep, fixed - thank you