For controlling the behavior when openning an external link (from a different program) there is `browser.link.open_newwindow.override.external`. It can be configured to always open a new window, or always open a new tab in the last active window. However, I use multiple virtual desktops on linux and when I open a link (from anywhere, really), I'd like it to be opened on the current virtual desktop but also in an existing window if there is one. It should almost be as if the firefox on each virtual desktop behaves independently for this purpose though I don't think actually doing that (one firefox instance per virtual desktop) would be a solution since I do need to move tabs/windows around fairly often as well. Is there a way to do that with some settings?