Added a new keyboard shortcut to dim only the active tab: Ctrl + Alt + B on Linux/Windows, ⌘ + ⌥ + B on Mac.

You can change the shortcuts from about:addons -> Manage Your Extension -> Manage Extension Shortcuts.

Added 'Default Settings' for dimmer. Now you will be able to choose new tabs' behavior.

- If you usually dim 1 or 2 tabs and don't want to dim newly opened tabs automatically, choose 'The active tab only' in the Default Settings.

- If you dim all the tabs and want the newly created tabs dimmed as well, choose 'All tabs' in the Default Settings. (This is the default behavior.)

- Dim state is preserved across tabs
- Dim state can be overridden for tabs via add-on's pop up menu.

Dimmer v2.0.0 can:
- Restore the dim state after refreshing a page
- Restore the dim state after visiting another page

- Fixed: Dimmer was not working after refreshing a page.