To setup new tab's default permissions for non-specified hosts, it is recommended to use "Tab Permissions" with this.
Open setup window from tab context menu "Host Permissions" od add-on menu, input web site and set permissions, then click "Set".
"Host Permissions" is not a URL base access controller. It is host base, tab permissions controller. For example,
now you are visiting 2 URL, "http://abc.example.com/index.html" and "http://def.example.com/index.html", both index.html page contain png image "http://img.example.com/image.png".
If you ban the image host "img.example.com" by Firefox basic function, you will never see the image.
If you disable "Image" permission of "img.example.com" on this add-on, nothing will happen. Because you are visiting "abc.example.com" or "def.example.com".
If you enable image permissions of "abc.example.com", and disable of "def.example.com", you will see the image on "abc.example.com" tab, but not on "def.example.com" tab.
If both "Tab Permissions" and "Bookmark Permissions" are installed, priority is confusing a bit. In general, "Bookmark Permissions" has highest priority, next "Host Permissions", then "Tab Permissions".
But it will be decided by whether Tab Permission's "Inheritance" is enabled or not, the tab is new or current, location transition occurs in the same host or not, and so on.
When you open link in new window, some function may not work.
"Tab Permissions" "Bookmark Permissions" : 11.01.11.01 or later