You don't need all those for this add-on to work. Why would you need to access browser activity during navigation? And why browser history? Is Firefox going to turn into Google?

cookies enable and moz-extension://f8917805-87c8-49cd-bdf6-85517b4156d5 add to exception.
check dom.indexedDB.enabled is set to true.
Addon but they are not working.

Could you add the option to add tiles that are groups with more tiles inside?

Previous versions had a way for you to take a one click screenshot of the current webpage with a camera icon in your toolbar and it would assign it to the corresponding tile, making them look exactly as you wante, and fixing that issue of Firefox not assigning images to tilkes. Now the camera it is gone, and you have to do everything manually. Why you removed that awesome feature?