Ok, 0.4 here, question, how to start active research. Have girls to mate, have temple, have tech screen, nothing clickable, nothing like button start research or something. Clicking on tabs, lit or not, goes nowhere. What I'm doing wrong?
I was similarly confused for a while when updating to 0.4 from 0.11; presuming you are correctly accessing the tech tree through the button on the top right or through the temple, it's likely that you aren't meeting the requirements to research the technology.
If you hover over a blank spot in the box for a tech without moving your mouse, such as Ratkin Technology l, for a few seconds a secondary box will pop up that details the unlock requirements. For Ratkin Tech. l, as an example, you must have 5 Ratkins living in homes in your colony; Ratkin Tech. ll requires 5 Ratkins housed in upgraded Yeoman homes, and so on.
Once it's unlocked, indicated by the box being lit up instead of grayed out, you can just click on the box for the technology to start the research process (As long as enough homes are built near your temple). I was clicking on the boxes for the technology upgrades and moving my cursor off of them without letting my mouse stay still, so it took a while for me to figure out how to get it to work myself.
Hopefully this helps -- sorry in advance if you had a different issue.