One of the nuisances that one encounters after uninstalling Adobe Flash from the computer system is the constant reminder that websites make use of Adobe Flash to deliver content.
The Firefox web browser for instance displays the general message “Additional plugins are required to display all the media on this page”.
That message is displayed beneath the header area and above the website content in the Firefox web browser. It becomes highly annoying as there is only an option to install the missing plugin(s) but none to disable those warning popups so that they do not appear anymore since you made an educated decision to uninstall Flash on your system.
Update: Mozilla has added a new parameter to Firefox in recent time. You can set plugins.notifyMissingFlash to false to block Flash notifications from appearing in the browser. Load about:config in the address bar, search for the parameter, and double-click it to do so.
It is possible to close the message by clicking on the x icon but that does not prevent it from appearing again on the next page load.
The only option to disable the install missing plugins message in the Firefox web browser is to disable the warning message for all plugins.
To do that enter about:config in the Firefox address bar, accept the warning message if that is the first time to open the configuration and filter for the term plugin.default_plugin_disabled.
Setting that term to false will disable the missing plugin alerts in Firefox. Users should know that this will affect all plugins that are missing, not only the Flash plugin.
It is furthermore possible to disable the scan in known plugin directories. This can be helpful for users who have a plugin installed in Microsoft Internet Explorer for instance but do not want it to be used in Firefox.
The parameter plugin.scan.plid.all handles the scan of the plugin directories. Setting the value to false will stop the plugin scans.
The Firefox configuration contains a second parameter that seems to be having the same effect as plugin.default_plugin_disabled. The plugins.hide_infobar_for_missing_plugin seems to block those missing plugin messages as well. It seems redundant.