Allow to manually revive a building ghost. Simply place building on top of ghost, if the one being placed matches the ghosted one, the ghost is revived instead.

This is useful together with Start with Blueprints mod and Blueprint String like mods. You can import circuit network contraptions via blueprint and then revive the ghosts manually with this mod, preserving the circuit network settings (in vanilla game they are not preserved).

Only issue is that reviving buildings provided by other mods will very likely result in broken behavior.