Rated 2 out of 5 stars

Still works with installation of unofficial (by wg9s) De SeaMonkey 2.53.4beta 1 pre Mozilla/5.0 (NT 6.1; Win64; x64; rv:60.0) Gecko/20100101 Firefox/60.0 Build 20200604210008 (Default Classic Theme) on German WIN7 64bit.

But I had to drop it, because the add-on does not respect my preference "do not switch to newly opened TAB". That is very annoying for me.