I found that I had to start the research, click away from the workshop and then click on it again. Then the research completed instantly.
From what i can tell, not even that works, the research option simply seems broken.
It worked for me in the past, i havent played since like 1.2
and yes i am using the latest 1.4 trainer
[Edited by stealhtfire, 10/20/2019 8:55:24 PM]