Is there a Firefox extension that would block Washington Post popups at bottom RH corner of pages?

   Check the boxes for:
        EasyList/uBO – Annoyances

        AdGuard Annoyances

   Click the orange Apply changes button at the top.

   *Right-click directly on the unwanted box.

   *Select Block element... from the context menu.

   *A red highlight will cover the box; click Create in the lower-right preview window.

''' Install uBlock Origin''' * Open Firefox for Mac and navigate to addons.mozilla.org. * Search for uBlock Origin (by Raymond Hill) and click Add to Firefox. '''Enable Annoyance Filter Lists''' By default, content blockers focus strictly on advertisements. Enabling built-in "Annoyance" lists prevents bottom-corner slide-ins and floating widgets across news sites automatically: * Click the uBlock Origin icon (red shield) in your Firefox toolbar. * Click the Settings/Gears icon to open the dashboard. * Switch to the Filter lists tab at the top. * Expand the Annoyances section by clicking the arrow next to it. Check the boxes for: EasyList/uBO – Annoyances AdGuard Annoyances Click the orange Apply changes button at the top. '''If a box still slips through''' News websites occasionally update their layout code. If a specific popup ever persists after applying the steps above, you can remove it in two clicks using uBlock's built-in element picker: *Right-click directly on the unwanted box. *Select Block element... from the context menu. *A red highlight will cover the box; click Create in the lower-right preview window. Firefox will save that rule permanently and prevent that specific element from rendering on any future visits.