Can't dismantle harpoon/crosbow with light from being built

[Nalk]

If I am building harpoon with light once I place it and confirm build mode, I can't cancel it. I can downgrade (no light) and upgrade back (with light) but there is no dismantle button.
IIRC it is same for mounted crossbow with light.

Also I think I could dismantle until I researched that option to have turret +light.

[Gabthelazy]

It's a problem with the UI. Try a UI mod, the option might be visible. From experience, the popular Dark UI mod has a barely visible Disassemble option while vanilla just doesn't show it at all.