Private Browsing Incompatibility

Wasabee doesn't have full compatibility with Private Browsing in Firefox. This happened when Wasabee changed from localstorage to indexddb storage. The workaround may be to add some code to your version of Wasabee.

About:config in the address bar then set dom.indexedDB.privateBrowsing.enabled to true

The other workaround is to use Chrome.