Firefox forces extension to have all their context menu additions in a submenu, this cannot be changed. I am confused as why you are having to click through the options, you should just be able to move the mouse, and it shouldn't vanish halfway through navigating.

For support, issues or suggestions please contact me or visit https://github.com/fnxweb/urllink/issues — in particular, see https://github.com/fnxweb/urllink/issues/5 for reducing the sub-menu count.