If you need to peel Firefox's menu off the front of the site's custom context menu, tap and release the Alt key.
I don't usually use touch on Windows 10, but what I see is: press and hold on the link => selection handles appear, then a little square zooms up, then when I release my finger, after a moment a very widely spaced context menu appears If you think the page might be blocking the context menu -- this would only be a factor on some sites -- you can override that so you always get Firefox's context menu: (1) In a new tab, type or paste '''about:config''' in the address bar and press Enter/Return. Click the button promising to be careful or accepting the risk. (2) In the search box above the list, type or paste '''contex''' and pause while the list is filtered (3) Double-click the '''dom.event.contextmenu.enabled''' preference to switch the value from true to false If you need to peel Firefox's menu off the front of the site's custom context menu, tap and release the Alt key.