TL;DR
I would like a different color to be used for techs already in research queue and techs not in queue.What ?
It is possible to queue technologies, even when their pre-requisites are not yet research, as long as their prerequisites are in the research queue.However, I have trouble differentiate at a glance which of those techs are already in queue or not, especially with techs around robotics which have similar silhouettes. See screenshot below for example :
In this situation, I'm wondering whether Worker Robot Cargo Size 1 is in queue or not, and I have difficulty telling it at a glance. A different shade of yellow (or another color) could be used to indicate that a tech is already in the research queue.