To start, both Windows and Firefox are running latest versions as of now. I recently found that Firefox had a list of frequent sites being displayed by right-clicking on any of the Firefox tabs in the Windows taskbar. I found that to disable this, I need to use the "browser.taskbar.lists.frequent.enabled" flag in "about:config". Setting this to false indeed disabled this, but it was replaced by "Recent" tabs instead. There is also "browser.taskbar.lists.recent.enabled" flag but this does not affect whether or not the Recent tabs list is displayed. Nor does "browser.taskbar.lists.enabled", nor does changing the max number of list items. The closest I can seem to get it to displaying nothing here is to keep the Frequent list active, and set it to a max of "1" item. Anything else displays a long list of Recent items. I don't think this is correct behaviour for these flags... If anyone has any other ideas here, that'd be great, thanks!