Hey there, sorry to be a bother, im currenlty playing with krastorio2 and SE, i seem to not be able to see a preview of the building after ive researched it. I've checked the player mod settings and fiddled around with it and cant seem to fix it. Perhaps others have had this issue and its been solved or its a bug of some sort!?? Thanks for taking time out to read.

From the FAQ:

Q: How can I see into factory buildings from the outside?

A: Research the "Factory preview" technology, and a toggle button with a factory building symbol will appear in the top left of your GUI. Whenever this button is toggled on and you hover over a factory building from outside, a preview of the interior of the factory building will appear in the top left corner of your screen.