Why does the research item have a blue bar?
There are 3 research items in my screen shot.
One I am researching, two others which are boosted. One of the boosted has a blue bar (Wheel). Why is it blue?
BOOSTED: Mine a resource
I boosted Bronze working by killing barbarians.
I boosted the Wheel from mining.
Also, I am china and china gets a 60% tech boost on eurekas. I started one turn of bronze working and now the bar is blue same as the wheel.
I decided to research for one turn Masonry but the bar did not go blue.
In regards to bronze working, the blue semi circle means you have already boosted it. It is to show that the research time is already reduced from the maximum.
The reason why the blue bar at the bottom lights up when selected is to just signify that you are researching a boosted technology (Kinda pointless i know) but there is nothing more to it than that.
Hope this clears things up.