Firefox showing blank AddOn window (PrivateMode) on icon click!

[LCF-AT]

Hi guys,

a longer while ago I was trying out some VPN extensions in Chrome & Firefox and I found some of them who having those blank AddOn window when clicking on them but just in private mode of Firefox (I use latest version: 104.0.2 64-Bit). Somehow that problem was never fixed in any future releases and I just wonder why not. I found a similar problem here too...

https://community.logmein.com/t5/LastPass-Support-Discussions/LastPass-extension-window-is-blank-in-Firefox-Private-tabs/td-p/277225

....with a extension called LastPass. Same problem / blank window on icon press just in private mode. So in my case I found two AddOns who having that problem...

Hotspot Shield Free VPN Proxy - Unlimited VPN - 5.0.10
https://addons.mozilla.org/de/firefox/addon/hotspot-shield-free-vpn-proxy-/

VPN Free – unbegrenzte Betternet VPN-Proxy - 7.0.10
https://addons.mozilla.org/de/firefox/addon/vpn-free-betternet-proxy/

...so both are from same author. Just would like to know why Firefox does show them blank in private mode and how to fix that. Must be an Firefox bug (I guess). All other AddOns I have tested are all showing their popup window in private mode.

greetz