The tech tree (research) is not fixed , at least in HTML5 , it is not fixed
I do 4 screen capture to show
1. When I open tech tree, I am in amuni chapter, the display like that
2. When I jump to previous Elemental chapter with lower button, that is the display...yesterday, it still show full tech tree, today..EMPTY
3. When I jump back to amuni chapter with lower button, all tech are there..BUT BUT BUT
4. when my mouse move to ..or try to open with mouse...some time it is ok, sometimes not ok...but some tech are gone