That tab you are hovering is “special” (because it has a protected domain addons.mozilla.org, there are a couple of them ) addons can not inject content so i assume generating a screenshot also wont work here.
Also the addon wont be able to generate previews if the tabs are discarded, so the tabs need to have been active at least once in the current sessions, otherwise there also wont be a preview available.
Well … in my case the hover cards dont show up at all.
The tab image generation seems to work, from what i can see when i debug the capture loop, so i assume there is some issue with the CSS theme.
In my case, it just shows a black rectangle :( https://fedia.io/media/f0/18/f0180aa24497689d44b0e199a6e0617f8a6628f12466257fb10dfeda004629e4.png
That tab you are hovering is “special” (because it has a protected domain addons.mozilla.org, there are a couple of them ) addons can not inject content so i assume generating a screenshot also wont work here.
Also the addon wont be able to generate previews if the tabs are discarded, so the tabs need to have been active at least once in the current sessions, otherwise there also wont be a preview available.
Thats what i gather from my own knowlege and from this issue https://github.com/easonwong-de/Tab-Preview-On-Hover/issues/1
tldr;
Hope this info helps.
It didn’t work on the google search page either :(
Is it working for you?
Well … in my case the hover cards dont show up at all. The tab image generation seems to work, from what i can see when i debug the capture loop, so i assume there is some issue with the CSS theme.