This doesn't work for me, I still get "Cannot connect to wire" when I try. However, the labs' GUI does show the "Circuit connection" side-window.

The tooltip on the labs says "Base mod > Disco Science > Space Age >Mining drones > Updated Construction Drones" for me. I would expect "Lab control behavior" to show up in that chain?

There's nothing in the logfile, no warning or such thing, nor is any error displayed.

screenshot of the entity please.

I thought I ran into the same problem, until I noticed, you seem to have to click on the lab's "southern central" part, like it's shown in the mod's image... after I found that out by chance, I can connect a wire to the lab.

maybe that's the same issue you experienced?

Is it really not that straight forward for people to click on the visible circuit connector? :D

:-D I don't know, I just clicked somewhere on the lab and wondered why it doesn't work... I believe that for all other Factorio buildings, it doesn't matter where you click it. But I never give that a thought, it just works - maybe I just got used to how other buildings work. :-)

Yes, that was it.

Is it really not that straight forward for people to click on the visible circuit connector? :D

Visible? It is in a sense, but in another it isn't. In Factorio, the displayed graphics don't really matter regarding the player's interaction. For that, the yellow frame that shows up when hovering your mouse is all that counts. There is only a single building where you have to aim your click according the the building's graphic instead of the frame (the power switch). So unless you by chance hover over the connector and notice the extra selection frame, it is invisible. At most you think "in a vanilla building, those connectors would be invisible until a wire is attached, but it's a mod, so it's fine."

And, by the way, after connecting over two thousand labs manually one-by-one, that "it would be too much work to make it copy&paste-able" has a really sour taste to it...

why connect two thousand labs? just connect one and set it to surface mode in the gui of the circuit connector.

Is it really not that straight forward for people to click on the visible circuit connector? :D

NO
connector is hidden well, especially with ALT view mode and even more with modules inside (not to mention ScienceGalore mod). Until you mention it, i can't found place to connect cable to BIOLAB

fair, i guess the module preview does get in the way of the circuit connectors, luckily the mod's thumbnail still shows clearly where the poles are.