A while ago, the "Daylight" release obliterated Firefox's features and left the UI buggy and badly designed. Even standard features like address bar suggestions are astonishingly bad. They've barely fixed anything since then. Imagine trying to read in one tab, type in another, and having each unload as you switch between them, for months. It's pretty clear that Mozilla doesn't care about offering a good experience on mobile; Firefox for Android is pretty much the new IE6, left out to rot.