This is just awesome! I missed Load Tabs Progressively very much and this is the perfect replacement. I regularly open more than 20 tabs at ones and without this great add-on some content is not loaded because the loading runs into a timeout. Now I just can limit the number of loading tabs to e.g. 3 and everything will be correctly loaded. It is absolutely beyond my comprehension, why such a functionality is not build into Firefox by default. Thank you sooo much!